GMC Safari/Chevy Astro Heating / Cooling

bax

I have a '94 Astro bought used a year ago. Took it on a 3000 mile round trip last summer with no problem. Now has 45K. A week ago suddenly there was a smell (intermittent) coming through the vents from the engine when the fan is in the "VENT" position. Does NOT happen with AC on. Oil, trans, coolant levels all OK. Thought maybe it was a refrigerant leak on the engine. Took it to a Chevy dealer, who could not duplicate the condition. (Told ya it was intermittent.) NOW it appears that maybe the smell wasn't coming through the vents (though I could have sworn it was), because I caught a little wisp of smoke coming from the fan switch. Dealer's electrical expert says nothing to worry about, could just be dust on the switch. This is a reputable dealership that says they try to avoid unnecessary parts replacement & expenses. I'd like to resolve this before taking another long trip next month and am strongly leaning toward replacing the switch, anyway. Feedback? Similar experiences?

mlctoo

HAVE 131K MILES ON 1992 AWD EXTENDED WITH HIGH PERFORMANCE "W" MOTOR. FOR PAST 2 YEARS, ACCELERATION/PERFORMANCE/DRIVEABILITY DETERIORATE AS OUTSIDE TEMPERATURE INCREASES. WHEN FIRST STARTING AND STILL COLD, MOTOR RUNS STRONG AND SMOOTH. AS IT HEATS UP DURING HOT WEATHER, THROTTLE RESPONSE BOGS EXTREMELY, AND AIR FLOW THROUGH VENTS DECREASES IN DIRECT PROPORTION TO ANY SUDDEN INCREASE IN THROTTLE. HAVE HAD EXHAUST SHOP DRILL HOLE AND CHECK CATALYTIC CONVERTER--CHECKS OK. HAVE SPOKE WITH NUMEROUS TECHNICIANS/SHOPS WITH NO RESULTS. IN POST #57, DECARBONIZING INTAKE MANIFOLD WAS MENTIONED, THEN REPLACING PLUGS AND O2 SENSOR. COULD THIS BE A FIX? PLEASE HELP, THIS HAS BEEN DRIVING ME CRAZY FOR 2 YEARS. DURING COLD WEATHER, DRIVEABILITY/RESPONSE STILL DETERIORATES SOMEWHAT AS MOTOR HEATS UP, BUT NOWHERE NEAR THE SAME AS WHEN OUTSIDE WEATHER IS ALSO HOT.

balashj

1996 Safari I had to have the rear ac hoses replaced. Now 14 months later the hoses have worn out AGAIN! Anyone had this experience? I feel that GM should pick up the bill since it is a design flaw. I am tempted to have them disconnect the rear air all together, but that would leave me with an option that I paid for and cannot use. This Safari van as far as I am concerned is a piece of junk. Any time the Service Manager is involved he is able to snake his way out of the issue. Here is a breakdown of the service I have had since buying the van in 1997:
33K - Hatch struts - covered under warranty
34K - replaced front end shock - warranty
34K - roof gasket - warranty
45K - front end tighten loose transfer mount bolts - no warranty
45K - Front end problems again(shimmy) replaced brake pads - no warranty
45K - O2 sensor - extended warranty
62K - AC blowing cold rear ac hoses replaced - no warranty
62K - Drivers side power window bad - no warranty
65K - Idler arms replaced after eating tires - Extended warranty
68K - Heat Control Valve - no warranty
76K - Replace passenger door handle and latch - no warranty
78K - Ac bad again.......
Is this typical for a GM vehicle?

biggr

hi,do any of you have rear heat that stays cold?i have a 96 astro with rear heat and a/c.the heat is as cold as a/c.i tried cracking the lines leading to the rear heater core to see if there was air,but it wasnt.the front heat works fine.is there a valve,switch or anything that controls the flow of antifreeze because it was cold coming out the lines when the front was hot

jlflemmons

Yes, at least on my '95 there was a heater control valve mounted just above the transmission. Follow your water lines from the heater core and you will find it. On mine the opposite was true. Heat all the time. The vacuum line from the switch was pinched off and the thing stayed on for years. The dealer told me it was supposed to stay on. Idiot. By the time I figured out what was happening, the vehicle was well out of warranty, the valve was stuck in the open position, and a replacement was only available from the dealer for $75. So, I just took out the valve and went to straight heater hose. Figure I lived with it for four years, I might as well continue. Another option is to get a cable controlled heater valve and install it in place of the vacuum unit. Then use a decorative choke pull off mounted to the heater box and run the cable to the valve. You will be able to turn the water on and off from the drivers seat, or the rear seat passenger can do the same.

Jim

biggr

thanks.i saw a valve just under the a/c box with about three heater hoses and it has a vacuum line as well as an electrical connection.i was checking it out in the cold last night so all i checked was if it was getting juice,and it was.i didnt check the vacuum.its kinda tight in there.

chris705

Hope someone maybe able to suggest a solution to my problem? The climate control is "stuck" on the defrost duct work only. That is I can not get the air to flow out of either the foot vents or the face vents. The AC and heat work but only come out through the defrost vents. Not sure if it is the control knob or possibly a pnuematic control valve under the dash? Any thoughts would be helpful?

jlflemmons

You have a vacuum leak in the controls. Could be as simple as a line came off of the control, or the vacuum line or canister is leaking under the hood. Classic vacuum problem.

Jim

ganze1

I have the same problem with the rear heater not putting out any heat. A valve has been mentioned near the A/C Unit. I believe I have found where the three hoses come together. I was wondering if you, BIGGR, found the problem and were able to fix it? Also, do you have to go from under neath to get to the valve? Thanks in advance.

67firebirdconv

I had the same problem earlier this year. Found the main vacuum line from the top of the engine to the main control juntion had become brittle and snapped off. The line had been installed over the top of the engine and the years of engine heat made it weak. You can buy the replacement part from the dealer, or splice the remaining good line with a more flexible hose from Autozone. The latter option is the cheapest way to go. If you do it yourself, you will have to remove the shroud from inside the van to access the main vaccum line to the control unit. The other end is accessible from the hood outside. Good luck...

biggr

ganze1,i havent fixed my rear heat or should i say i havent attempted to try to fix it yet as i've been too busy and its been kinda cold out.i just fixed my gp tonight so i can pull it out of the garage and work inside.i may make an attempt soon and let you know.the rotors on my 96 astro seem to be a little warped but i have almost 90k miles and im due for a front brake job anyway.the sensor is scraping and driving me crazy!!!

chris705

67firebirdconv you're the best! Went right to the vacuum line (very small - 1/8" dia.) and it was completely broke in half. Went to the auto parts store to buy a 3' replacement length for under $10. Now works like a charm - just in time for the winter driving. Thanks tons, you guys saved me a bundle!!

jlflemmons

If your dealer can't figure this one out in like, oh, maybe three minutes, you need to find another dealer. Safari's have vacuum operated ac routing. I'm betting you have cold air, but it either blows out the heater ducts, or the defroster ducts. Either way, it is almost always a vacuum leak. On my '95, it was a pinched vacuum line in the dash.

Jim

jlflemmons

Check for freon loss. If the system pressure is too low (no freon) the pressure switch will not let the clutch engage. To do so would damage the compressor as without freon the lubricant does not move through the compressor and things tend to come apart. If you have rear AC, be sure to check the lines running to the rear evaporator core for damage.

I, on the other hand, am having to replace the compressor on the wifes '95 model. It still will freeze your cheeks off, even here in Texas, but the internal bearing, not the pulley end, is going bad and the thing sounds like it is about to come apart.

Jim

jrekj

My 97' GMC Safari has been reasonably reliable since I bought it new. But now with it being seven years old and 84K miles it has its occasional problem. With the weather now getting warmer it was necessary last week to use the A/C for the the first time this year. The A/C properly engaged, but all the cold air would only come out of the defroster vents. I suspect a vacuum leak, but how can I verify it? Do I need to take off the entire front dash to trace out the vacuum line? (My concern here is that the airbag that might prematurely engage). Any suggestions or comments would be welcome. Thanks.

tucker2

I had the same exact problem that I fixed yesterday. It was the very thin plastic vacuum line that runs from right behind the silver AC tank on the left front of the engine when facing it under the hood. To test it disconnect the tube at the "T" and feel for vacuum. If no vacuum this should be your problem. You will need about 4 feet of large windshield washing rubber tubing. Connect the tubing to the the fitting on the "T" and the other end to a connection at the center of the left valve cover (when in the drivers seat). You will need to remove the housing that covers the engine. If the leak is behind the dash, it is very easy to remove the dash to get at the AC controls but I do not believe it is necessary.

rastro

The Climate Control fan won't blow through the top vents on my '00 Astro. Thanks to the rear air it isn't totally unbearable but summer is rapidly approaching and I need to figure out
what I might be able to do before hauling it in to the dealer. Can anyone tell me what could be the problem. I'm not certain if it it mechanically or electrically controlled, a linkage or switch issue and would like some direction before tearing into the dash.

jpallardi

It's probably the tube in the dash, these things are controlled pneumatically, and the tubes get holes in them when they dry out, tubing is .50 a foot, but the engine cover and dash removal is what costs you, find a good independent guy I had mine fixed last summer for @ 35.00 or so, if you try yourself it really is pretty simple

mclean

did you have any luck
i have a 2000 safari. air only comes though the defroster for the windshield and at your feet

97xpresso

My 98 Asstro had the same problem, it looks like a melted vacuum hose that runs too close to a manifold in the tight engine compartment is to blame. I tried to rig up another hose, didn't have the right size so a cardboard duct on the dash cooled me off. I now drive an '05 Asstro for my company, it's amazing, they're so similar, you can't tell the difference.

cob

I have a 97 and the air only comes out the defrost or the floor. Is it just a vacuum line on the engine or is it a line behind the dash on the back of the climate control panel? If I switch to A/C the compressor kicks on but the air doesn't come out of the vents it stays at a combination of the defrost and the floor vents. Can anyone diagnose before I take the entire dash apart to find out?

97xpresso

It's a vacuum line on (over and too close to) the engine which was damaged. You have to have really long arms to reach from the front hood area.

cob

Is it easier to reach by removing the doghouse?

tkw

Hi 97 xpreeso:

I have the same problem on my '98 Safari. Can you tell me more about where to locate this vacuum hose? Is it accessible from inside with the doghouse removed? What make you decide not to replace it with new parts?

I have got hold of a Haynes Repair Manual but it's no help at all. I too like to investigate more to decide if I have to take the dash out. Thank in advance for your advice!

97xpresso

The reason it was not properly repaired is that it was a company vehicle that they did not want to spend $ on. I now drive a 2005 Astro, and the air actually comes out the dash, but for how long? A co-worker claimed he had success with a neighbors Astro and I watched him try to fix mine. I believe if the proper diameter hose was available it would have worked. Standing in front of the van the hose came out of the dash just off center towards passenger side. It then curved downwards 180 degrees across the top of the engine where heat deteriorated the hose. It probably would be easier to remove the engine cover. Good Luck.

cob

I found the vacuum line on my 97 that had broken. The line starts over behind the a/c evaporator on the passenger side of the van right in front under the hood and goes across the motor and hooks to a fitting on the intake manifold behind the a/c compressor. I routed it above the air cleaner to keep it cooler instead of along the intake manifold where the factory routed it, time will tell if this lasts. That line fixed the problem and now the air comes out wherever the knob is set to on the dash. I removed the air cleaner cover and the tube that connects it to the rest of the air intake and it was easy to fix from right under the hood. The vacuum line is a real small diameter plastic tube with rubber connectors molded to each end. You can't hear the vacuum leak with the engine running since the hose is so small.

markthecarp

I love my astro but am having some probs at 140k. My wiper motor has gone intermittent. (A bad thing in the daily fog drizzle we have here every day this time of year) I saw a fix earlier that suggested re soldering connectors at the circuit board. Can someone tell me the location of that board so I can find it without having to go through the trouble I did locating the wiper motor? Click and Clack said it was under the dash by the glove box. So I hauled everything out only to find the motor under the hood which required cutting of the protective housing to remove.

When the motor came out I dissected it expecting to find worn or hung brushes. I had neither! Everything looked fine. I had tested and found voltage to the unit before removing it, but now suspect that maybe the voltage that registered on my digital Radio Shack cheapie maybe didn't have enough amps to turn the motor.

Any ideas?

My directional air controller has failed as well. But from reading previous fixed I'm going to have to look at the vacuum line.

My A/C left sometime last year and I can't tell if the clutch is engaging or not. It worked fine always good and cold until that point. I would appreciate some advice on how to begin trouble shooting that system.

Why do I love her with all these problems? Unlike my wife, I've had her since new, and she's proved WAY more reliable and predictable.

Thx in advance for any and all advice.

cob

Check with you r dealer about a recall on the wiper motor. GM recalled all of them in trucks and vans over about a 3-5 year period 96-99 or something to that effect. I had mine replaced in the 97 for free last year. As I explained before the vacuum line is an easy fix. You can tell if the clutch engages because of the extra noise it creates engaging and disengaging. The engine also changes speed up and down during that process. Good luck on the repairs.

tkw

I've got to try this one. I should have check this forum before I went on the wild goose chase under the dog house last weekend. I tried to tackle this same problem from under the dog house without success. BTW, does anyone know how to remove the dog house without taking the passenger seat out. I can only manage to turn to side way to get access to the engine.
It was unseasonably warm last saturday,over 90 degree F. We usually don't get this weather until way into July. Now, DW is threatening to file for divorce if I don't get A/C to come out from the dash outlet. :mad:
Anyway, thank cob for the tip.

tkw

Hi cob:
I found it. It was broken in two places and lying on top of the thermostat housing. There's actually a flat spot on it resulted either from heat or rubbing against some moving parts. Without your descriptive & helpful explanation, I'd never suspect this stiff dingy 1/8" hose is a vacuum hose. I was looking for a 1/4" flexible rubber hose all along. BTW, did you buy the replacement hose from auto parts store in bulk or you have to get it from the dealer.
Thank you in advance!!!

tkw

I yanked the hose from its fitting at the evaporator end and took it to Canadian Tire this morning. The guys at the service counter have never seen such a vacuum hose. No luck. I will try a few other auto parts store before I hit the dealer b/c they are normally three times the cost. Suggestion anyone please?

cob

I got my hose from the dealership. I then routed it over the plastic air intake to keep it cooler so it would not melt again. I guess they make repair kits for the hoses but it is a cheap part even at the Chevy dealer. You can get the doghouse out without removing the seat I have done it a few times. You have to move the seats back all the way and pull the cover straight back. When you lift it out you will have to compress the corner of the seat cushion to squeeze it by and it takes alot of jimmying but it will come out. Putting it back on is a little easier.

tkw

I placed an order at the dealer this morning and picked up after lunch. It was surprisingly cheap, under $10 CAD. I tried 3 autoparts store to try to get longer ones so that I can reroute it out of harms way without success. I know you have to get the whole assembly from the dealer with the end fittings and afraid that it may be in the range of $50. How often you can get away with $10 from the dealer?
The downside is the re-routing option will be limited by its pre-determined length (800mm). I read it here that a fellow member has replaced his from under the hood. I will try my best not to touch the doghouse. I did it last weekend and it really sucks!
Anyway, thank you for your help and wish me luck!

tkw

Hi guys:
A big thank you for all of you here who shared their experience. Here's my update.
I replaced this vacuum hose thing from under the hood this morning with some difficulty. But it is doable if you have small hands like me. At one point, I almost have given up and attempted to take the dog house out. From under the hood, first I removed the air filter, air intake housing and the electrical connectors. Then I picked up the old hoses piece by piece on the manifold and traced it to near the back of the A/C compressor. I had the rubber fitting held between my left index finger and middle finger and stuck there. I didn't have any room to get my thumb on it to pull it out. I wondered it'd help if I have all thumbs.
To avoid wrestling with the dog house, I reached in and removed the wing nut securing the metal bell housing over the throttle body. This gave me an extra inch or so to pull the rubber fitting out. The new hose from the dealer is barely long enough to allow rerouting over and away from the engine. And now that we finally have dash A/C, it is raining out there today.
Sorry for the long post. To keep the record straight, this so call vacuum hose is actually a vacuum signal tube for HVAC control. Its GM part no. is 15967970. It is 1/8" O.D. x 800 mm long. I hope this would help those who has this nagging problem.

wmrhere

In 2 words - vacuum line.

I have a 97 Safari which has had the same problem. The factory supplied tubing is less than 125" O.D., and runs from the top of the manifold about 20 - 30 inches. In my case it was glossy black and really brittle after heat exposure. I ultimately replaced the entire length, after 2 unsuccessful problem area replacements.

cob

I have a 1997 that is a conversion van by Glavel. The rear heat/a/c was installed by them at an aftermarket company. There are freon lines and heater hoses running to it so I would assume it would work for both a/c and heat. However the control for it is just a 3 speed fan switch. The unit always blows warm air no matter what temp I have set on the dash control. The a/c portion is an extra evaporator connected to the factory unit and there is a sticker under the hood that states they put in x amount of freon at this company. My dash factory a/c blows cold (so I know that the freon is not leaking)but the rear one blows warm air. Is there a valve somewhere in the system that may be stuck for the temp control to the rear unit? If there is where can it be located? If anyone else has this setup or has some answers please reply, thanks.

Claires

cob, you might also want to bring your questions to the folks in the Climate Control Problems: All Cars Forum to see if they have any answers for you.

ClaireS, Host
Coupes & Convertibles | Vans & Minivans

tkat

Look here for the Vacuum hose issues on your AC, it may just be cooling your feet, as the diverter is not getting any/enough vacuum. As to the wiper motor, unbolt it partially, and clean the copper grounding strap you'll find on one of the mounting bolts. It's a poor combination of two dissimilar metals, and corrodes after about 5-7 years. Result: no ground, no wipe.

jpc47

Turned out to be a melted vacuum line going to the ac control. My mechanic spliced a piece in and now I'm fine.

poopscooper

Just last week my 96 astro will only blow air out of the defrost and floor, like it is stuck on that setting even when i try to make it blow out of the dash vents.

Where do I even start to fix this problem???

Thanks allot!

cob

Look back a couple of pages and you will see many posts on this issue. It is a common problem that the plastic vacuum line from the passengers side front of vehicle by the a/c components that runs across the engine to a vacuum port on the drivers side of the motor. The line melts and you lose the air settings. It is a cheap part and try to route the replacement line over the plastic air intake so it doesn't melt in the future.

rrc60

I recently had same problem. Fix was made by replacing vacuum line from manifold to A/C condenser box. The climate control valves are run by vacuum. Most likely you have a small vacuum leak.

13tigger

I have a 95 GMC Safari Van that I can't keep the relay working. The lower fan speeds go out, I replace the relay in the duct. All speeds work then for about 6 months then I need to replace it for the same reason. Does anyone know why I can't keep relays? Thanks 13Tigger

demaziii

There is a valve on one of the tubs coming from the compressor,it has a black cap,it is approximately 1" high, remove the black cap (unscrew cap to remove) to get to the valve (you can open or close valve with a flat screwdriver)

cob

I found the valve. There were 3 different valves with black caps on them. One looked like the spot to fill the freon with a valve stem in it. Another one looked like a check ball in it for possibly discharging the system. The third on one of the lines had a stem sticking up about 1 inch that was round and came to a square at the top which could be turned with a wrench. I tried turning it left and right but it did not move either way. I did not want to put too much pressure on it fearing I would break it and let all the freon out. Is this the correct fitting? If so what is it supposed to be doing? If I turn it does it allow the freon to go through the line to the rear unit? Does it balance the pressure between front and rear? I could use some more input if you have any thank you. FYI while on a 5000 mile road trip last week when I had the dash control set on max a/c sometimes the rear unit would blow cold air especially when it was cooler out but, when we were in the southwest it just blew hot air from outside 100-115 deg.

pzmom

My air-conditioning quit blowing out into the cab low to high in Max A/C, A/C, or vent mode. Defroster works (blows cold air). Rear A/C works (I understand they are two different systems). I can hear the blower running. I checked the fuses, but they seem to be okay. I can't find anything in the manual on how, what, or where to check. Any ideas? Thanks!

eharston

I just fixed this same problem on my 2000 Astro last night. The vent system is vacuum operated and a vacuum leak will cause the symptom you have described. The most common cause on the Astro/Safari is a cracked vacuum line that runs across the top of the motor towards the front. The vacuum line is exposed to high heat continually and gets brittle and begins to crack in numerous places. The reduced vacuum causes the A/C vent selector to not operate properly. The vacuum line has 90 degree rubber elbows at each end and the rest of the line is very small diameter plastic tubing. One end it accessible under the hood on the left side near the A/C equipement, the other end is accessible if you pull the engine cover and is on the driver side of the intake manifold. I just replaced the whole vacuum line with rubber vacuum host and rerouted it off the top of the engine and put some shielding on it. HTH

tkw

There're lots of discussions on this subject on recent posts. What eharston posted is correct except that the entire job can be done from under the hood. It is a bigger job to remove the dog house than the actual repair. I found it out the hard way. You don't want to mess around with it.

machicj

i have a '99 astro and yesterday the rear a/c blower quit. i checked the fuse, (#12) and it looks fine. also checked the a/c relay under the hood, but don't know how to tell whether its good or not. any suggestions? thanks

a_recruiter

The Blower on my 1994 Astro will not blow on "High". The A/C Compressor remains engaged even though the fan doesn't blow. I replaced the Blower Control Switch in the dash thinking that would fix the problem. $29.00 later...the blower still will not blow on high. I am not an electrical whiz when it comes to trouble shooting . Any tips would be helpful before I go out and buy a resistor, fan motor,...a new van?

iwhitey

I have an ac problem that I can't seem to find the answer for. Basically, the compressor won't shut off in any position of the vent dial, even if it's off or the heat is on. Any ideas?