Chevy S10 - GMC S15 and Sonoma Climate Control

dkurrle

Has anybody else experienced air flowing through your vents, similar to if the fan was on low, when you have the knob on OFF. ??? any suggestions?

canufixit

Hi The Big Al !!!

(Now that they changed/ closed the general forum topic to read only ( a blunder in my opinion) - I find it hard to want to spend the time to jump through multiple discussions and read reply ... too bad. But good to find a post from you !! )

re: Fan - I think I remember reading that due to CO concerns the fan will never shut off - in case someone falls asleep in the vehicle - and/or the tail pipe get blocked (i.e., parked in snow). So I think this might be "normal".
The pain is that when you leave the flow path knob set for "Floor" - it gets hot air - especially irritating in the summer.
What I do is change the flow know to top vent set to Cold (not AC)- it seems to fix the issue. Air still comes out - but it's not hot and it's at least Not bothersome ...

dkurrle

yes it comes out all my vents in OFF< not just the floor vents.

jhatch

hi i have a 1995 chevy s10 has 150.000 miles and we can't get any heat, the fan works great! this is my sons truck and we are in the north east so were trying to get it to work before it really gets cold. any help or ideas would be appreciated

jsmothers

I have 1991 GMC Sonoma. The blower is not working. I have already replaced the blower motor. Anyone know where the blower relay is???

s1089

kinda sounds like my truck...only mine blew smoke outa it lol but it kinda sounds like a heater core to me....

mike182

I have a '98 Sonoma and am having heater problems. The heater only blows cold air. I have replaced the thermostat and the switches, but it still only blows cold air. The coolant level is good and the core isn't leaking. What can I do? Any suggestions?

canufixit

Hi,

When the truck is well warm - shut it down, open the hood - and see if you can feel if the heater hoses going to/from the heater core are BOTH hot ?? If only one is - Check to see if you have a vacuum run shut off in one of the lines - and see if it's open allowing flow... Could be a bad valve - or - vacuum not getting to the the valve (i.e. cracked vacuum hose ??)

Otherwise - it's possible that the core is plugged - or perhaps even air bound ???

Just a couple thoughts ...

chuk

I also have a heater problem. I have coolant smell in the cab.
I am trying to replace the heater core in my 2000 S-Blazer. I got the dash out and the heater/ventilation unit loose except for what appear to be 2 bolts coming through from the engine side of the firewall at the bottom. I am working from a Haynes manual, but there is no mention of these bolts. If I am right, the only recourse is to depressurize the A/C system & remove the evaporator to get to these 2 bolts. Seems ridiculous to have to do this to replace a heater core.

Looking for any help or advice that might be out there.

Thanks

chuk

I am trying to replace the heater core in my 2000 S-Blazer. I got the dash out and the heater/ventilation unit loose except for what appear to be 2 bolts coming through from the engine side of the firewall at the bottom. I am working from a Haynes manual, but there is no mention of these bolts. If I am right, the only recourse is to depressurize the A/C system & remove the evaporator to get to these 2 bolts. Seems ridiculous to have to do this to replace a heater core.

Looking for any help or advice that might be out there.

Thanks

chuk

Answering my own question. . . .

Finally determined that you have to go in through the right wheel well -- remove the wheel and wheel well liner (meaning you have to pull the battery, powertrain ECM, and the coolant reservoir. Once all that is out of the way, you can get to the 2 studs coming through the firewall, remove the nuts, and proceed.

chuk

Answering my own question. . . .

Finally determined that you have to go in through the right wheel well -- remove the wheel and wheel well liner (meaning you have to pull the battery, powertrain ECM, and the coolant reservoir. Once all that is out of the way, you can get to the 2 studs coming through the firewall, remove the nuts, and proceed.

hoodlatch

I guess the next question is, are your going to replace the two nuts?

steel24

Thanks. I'm working on replacing my heater core for my 99 s-10. Haynes doesn't mention those two bolts, among other things. I was hoping there would be an easier way to get to those bolts. Your post confirmed what I was dreading. But good to know anyway.

gonogo

I know I am coming in on the end of this thing, the GM SI states remove the passenger fender to replace heater core.
There is a mention of studs to remove, never did the job so not sure what they are talking about.
The GM SI for heater core replace is long and drawn out, like the job I guess.

steel24

SI ? And where do you get it?

gonogo

GM Service Instructions. Back when they had generic user name a P/W I got on the site for 3 months, some dude put it on line. Then they caught up with me and kicked me off.
In the mean time I downloaded MB's of files for my 2 vehicles.
Anyone can get on their SI site, but you need to pay with credit card. It used to be day, month and year.
Go here, no WWW. http://service.gm.com

lchristian

Chuk,

I have a 2000 Jimmy and I have to replace the heater core in it real soon. Thank you for posting this information about removing the wheel well liner. Did you have o discharge the a/c system? Are there any other tips you can offer before I start?

Thanks again,

Luke

darcy2

trying to improve cooling
using refill ez chill auto air conditioning r-134a refrigerant plus oil
could you please tell me were or what line to attach to fill it thanks

gonogo

Put in just plain 134a, the oil in the cans may not be compatible with your system. If you contaminate your A/C it will cost more then $1000 to fix.

brivers63

I searched and searched and could not find an answer to this.

Where is the a/c condensation drain hose on a 1998 GMC extended cab Sonoma? I am getting water in the cab on the passenger side, coming down from the firewall when the a/c is running and after it is shut off. I have looked under the truck as best as I can and cannot find the drain hose. Any help to put me in the general area would be appreciated.

gonogo

Well on my 99, look under the truck passenger side. It is where the firewall and HVAC unit come together at the bottom. Is a plastic tube about 2 1/2 inches long horizontal pointing forward. It is just aft of the ignition coils.

philscbx

WARNING
This Applies to all owners looking at coolant level.

Stop looking in Coolant over flow tank for confirmed level of engine coolant.
You'll get faked out every time.

You need to only look in radiator.

First sign of no heat is low coolant.
Second is plugged heater core.
Be careful and gentle when flushing out core to not over do it with outside pressure source.

You could force a weak heater core to leak all inside vehicle.

If you applied radiator stop leak in the past, then take a minor guess where all that crap is now.

If you have to use these products, then take out the heater core from the process by removing the heater hoses from the engine.

dragboats

hi all new to the site,i have a 2000 s-10 with 110,000mls. the vent control wont switch between defost and floor it stays on panel. any ideas what could be the problem?
thanks....

scoobydude1

Engine will not heat up over 150 degrees. I changed the thermastat and blocked the radiater but still will not heat up.Could it be a blocked heater core?

snowx132

uh yes im having problems with my heater, when i turn it on i get water that runs down on to the carpet out of the bottem of the dash. some one told me that it is a heater coil, if it is how do you take the dash off a 97 s10 to get to it ? need help despret!

hoodlatch

You'll need a 1/4 in drive set, Phillips and flat screwdriver, drop-light, and patients. Last time I removed and replaced the dash on my 97 I only had three screws left over. That's a personal best for me. Good luck

chuk

When I did my 2000 Blazer, I followed the Haynes manual. It wasn't perfect, but it had 90% of what I had to do. The dash, while somewhat intimidating, wasn't that bad. For me there was a piece under the dash that had to come out in order to get the heater core out. It took me hours to finally find the 2 studs that were poking through the firewall. I had to remove the right front tire and go in through the wheel well to get to them. If I had had good direction this would have been minor, but as I said, I lost hours just trying to locate these on the engine side of the firewall.

Good luck

mboes

I have a 99 S10 with the same problem. Did you ever get a solution?

Thanks

danpstew

when the control is to cool, there is warm air coming out of the floor vent, if the a/c is on max its cool coming out of the dash, not cold. whats to be checked? please advise.

gonogo

The first part is normal for the S-10, just put on the dash vents. With the A/C running, feel the large line at the compressor, is it cold.

danpstew

yes, the large line is cool the small line is warm.

gonogo

The large line at the compressor should be cold not cool, I would think you are low on 134a. It should be checked by a pro, the right way to fill a 134a system is recover and then add the factory amount back. I would say a leak check should be done also.

sn4ck0

95 S-10, I turn the heater on and the P brake light comes on, and the speedometer goes to Zero, Fuses are ok, every once in a very rare time, I would turn it on, and every thing works fine, but as I'd turn it back off, it'd maybe come back on once (some times it won't), then it won't work properly after that for ages.

I had read somewhere that it may be a Ground near the Dash Cluster, but I've no Idea where the Dash cluster is at, I've the repair manual as I've had to do many repairs to it, and in the Electrical Diagrams area, they list quite many, many grounds, many more than what I wish to check, I've check and cleaned the grounds in the engine compartment, all are swell.

Any Ideas?

Thanks in Advance.

gonogo

Your gauges are your dash cluster.Look under the dash for grounds.

sn4ck0

I have the entire Dash apart, and I'm not able to find any "actual" Grounds, anyone have an Idea to where the Grounds inside are located?

gonogo

The plug with all the wires, one or more is ground. Now you need to find out where they are grounded, close by I would say.

sn4ck0

There are about 10 Different Plugs, 4 or five of them, are rather "large".

boomerff373

I just noticed that my blower motor only seems to work on 3 and 4 now. I was just wondering if it is a bad blower motor or if the blower motor resistor is bad? Any help would be appreciated.

sn4ck0

I have heard the Same issues, with the HVAC Switch only working on "high" and the problem being the Blower Motor Resistor.

If your Blower Motor is working, I think you could rule that out, The BMR, is roughly 17$ of course depending on where you're at.

As I've just replaced my BMR, trying to resolve another issue, I know it's a simple task to to replace.

boomerff373

Ah okay, I was kind of leaning twards the resistor. I looked it up the other day, about 22 bucks at Advance Auto. Thanks for the tip.

03gmc

I have a 03 sonoma w/ manual climate controls. I have noticed that some one else posted a question about my same issue. With the temp selected to cold and the air flow off I get warm air through my heater, also if I select defog, heater, or blend I still get warm air which is very annoying when it's 60 degrees or warmer outside. Is this normal? All the other GM vehicles I've owned would actually blow COLD air if defog was selected. My A/C works fine. And I can hear my A/C pump engage when selscting defog. I checked my mixing actuator coming off the heater core and it seems to be getting full movement in both directions. Any suggestions?

gonogo

Sounds like the temp actuator is not moving the valve. Is the large line going to the compressor cold on A/C?

03gmc

Yeah, The a/c works fine. I was able to observe the temp actuator and it seems to getting full movement in both directions. There are actually reference marks on the duct that coincide with the actuator. They seem to line up also. The only thing I can figure is the temp actuator doesn't quite close the whole way.

gonogo

well with my 99 I have to have dash vent on, or I get heat out the floor vents. Dealer said normal, they all do it.
The A/C is so cold, I have to modulate with heat or I would freeze, even when 90+ out.

soccrfinatic13

I am having trouble with the Head/Feet control. It is a 2001 Chevy S10 with ZR2 Package. When I go to put the air to blow on my feet, so that all the air comes out the bottom, its as if i never moved the switch. It still comes out the top (face). Also when I try to put it on defrost, nothing happens. It only blows out of the 4 vents that point at my face. Any ideas as to what is wrong?

gonogo

Check for a vacuum leak. Under hood drivers side, the hose goes into fender well where vacuum reservoir is located. Trace it out looking for a problem.

the_big_al

Is the air coming through the dash vents or the floor vents? Dash vents should not be emitting air when the fan switch in the "off" position. When the fan switch is in the "off" position however, the floor vents will always allow air to flow through the vents. You will not notice this if the truck is not moving, but once you get wind passing over the truck while driving, air will flow through the floor vents. This is common on most GM vehicles.

Texun

I have a 98 S10 W\factory air that only cools under acceleration. I thought it was low on refrigerant so I bought a refill kit with a gage. It was at 35psi on the high side so I added just a shot and it's now at 39psi with no change. I do not have a full set of gages so I am unable to check the low side.

At cold idle the compressor kicks in and cools perfectly. However, once warmed up and at idle or highway cruising speed, the compressor no longer kicks in and the only way to get cold air again is to accelerate. As soon as I accelerate to pass a car the vents start blowing very good and cold air. I checked the low pressure switch on the can, and as far as I can tell it's not receiving voltage when engine is running and warm. As soon as I rev the engine the compressor will kick in again and blow cold air.

The compressor and dryer were replaced about 5 years ago and I have had no problems of any kind until recently. This has me stumped. I've got a long road trip ahead of me and I live in the south. Any suggestions would be appreciated

adashan1

I have an 03 S10. The vent control has a vacuum leak behind it that can be heard. I took it out and found the rubber piece which directs the vac flow had swelled so that it did not fit the metal backing piece which presses the rubber piece against the vacuum manifold. I replaced it and it worked fine for a while and then it swelled again so the noise is back and it doesn't work. Does anybody know what"s going on here?

clutchxr

I am having a similar problem with my 01 sonoma. The heat worked fine this morning but after work it would only work on 2 and 3. Would this more likely be the switch in the truck? My guess is on 4 its bypassing the resistor correct? I used a volt meter and at the plug for the blower i get no voltage when on 1 or 4.