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Pontiac Grand Prix Heater blower relay switch

perplexed3perplexed3 Posts: 2
edited November 2018 in Pontiac
I need to locate the heater blower relay switch.My heater only works on 5 and have been told it is prob the relay switch.Any ideas where it's located and where i can find a manual showing location??? thanks


  • The blower resistor/relay is located at the front of the blower unit which is on the passenger side by the firewall. It is a very awkward spot. Have you checked the 20 and 10 amp heater control fuses by the glove box to determine if you are getting power there? These are what actually controls speeds 1-4 and are fed from the ignition circuit. If you are having a problem with the daytime running lights also you might want to check out the earlier posts from late december where it details that most likely the ignition switch is causing the problem.
  • edpoedpo Posts: 1
    I have a really strange problem. I turn my heater fan on high(although fan speed doesn't really matter) When I am idling in problem. I start to drive and accelerate, the air flow thru my vents stops (although I can still hear the fan is on high)But if I ease off on the gas pedal....air flow comes back again. Step on the air flow....ease off air flow comes back. It's the strangest thing. I hope someone has an idea. :confuse:
  • hello, i have dont everything blower motor, fuses resistor. i still have only 5 speed lights go off 1-4. need help its cold here with heater not working right..
  • Check the fuses next to the glove box that are for the blower and heat control unit. If there is no power there then you have a problem in the ignition switch and will need to replace it. I just did this on my car and it fixed the problem with the Blower not working on speeds 1-4 and the DRL going off when the heat was turned on. A word of caution if you do replace the ignition switch yourself, when you disconnect the battery make sure you have the security code for your radio or you'll lock it out and will need to go to the dealer to reset it.
  • My 2001 Grand Prix's blower does not run on any of the 0-5 settings when I leave my 50 deg garage. It has been 0 to 5 degree ambient in the morning. After 10 min all switch settings work although setting 5 does not seem to be full power, but it's close. Leaving work (15 deg ambient) it comes on immediately and all the switch settings work. If I shut the car off it will not come on for 3-5 minutes. When the blower is running, it seems to decrease speed when I turn or slow down. This has been going on for a week.
  • I took the car to the dealer and they found water had leaked throught the cowling under the windshield onto the fan motor and the resistor board. The fan and board both had to be replaced & the leak was resealed.
  • i had all the same problems you have had.
    1. blower fan
    3.heating control assy.
    now i still have problems with only speed 5 after putting all that in. you would never guess what it is now.

    the ignition switch, not key put, the wiring part in the steering colume. that runing me 100.00 tommrow i will be putting that in. so to say i had all the same problem but after doing 1 thur 3 i had found that ignition switch is the problem when only 1-4 dont work and running lights go off. so keep eye on that because this sucks. i have been fixing cars myself for about 5 years. some isnt easy but trying to track the problem. i would have never guess ignition switch, that is what starts the heat in the first place. have a great time... christy
  • the blower and resister are behind the glove box. I just replaced both and had the whole thing apart. You actually don't need to take the glove box out to replace either. Just stick your head under the passenger side dash and you will see the blower. IMPORTANT NOTE: your motor and resister are probably bad because of a water leak. Check the water leak thread for help on that. I'm in the process of fixing that myself. Water Leak read #16.
  • :blush: Thanks I think that makes sense I have also had problems with ignition sticking and not being able to get key out maybe this is all related in some way Thanks. For now still working on 5 but I am sure it will stop again. :confuse:
  • when you turn it on 1-4 does running lights go off. after a while 5 will stop. you can get ignition switch (wires not key part) at advance auto. but there is 3mm 5/32 tools you will need couldnt find 3mm or 1/8 so taken 5/32 put pieace of paper in 5/32 to make it fit as 1/8. good luck with being a woman i can do you can. christy from PA
  • bollmanbollman Posts: 1
    I have a electrical problem with my Grand Prix 2002. I replaced the blower motor and resistor about 6 months ago do to the known water leak with the seal below the windshield.
    The problem now is when I turn on the blower motor switch the car lights do not work, the car monitor on the console doesn't work, the seat heater doesn't work, and you have to manual turn the headlights on for them to work.
    Does anyone have any suggestion's on what might be going on?

  • I'm having the exact same issue with my 97 Grand Prix. I posted it under "1997 climate control problem". Its the strangest damned thing and the only thing I can even think is that its a vacuum line leak or check valve on the line. :confuse: The only difference is my air flow goes from the vents to the floor. Something is making the blend door in the dash move when I hit the gas... I'll let you know if anybody gives me any other ideas. Let me know if anybody does the same for you. Good luck!
  • christy10christy10 Posts: 19
    I had the same problem, and it wasnt the blower motor or resistor, it was the ignition switch wires, that controls the main heating parts. There is Orange wire in the ignition switch that was going bad. I would change that before going into other things it might not be. My lights wouldnt work and i had to turn manuel on. so i have had everything wrong with heat . I change the ignition switch and now it works great.
  • tiklirtiklir Posts: 1
    My wife's radio/clock display is so dim it can only be seen with a flashlight...I also noticed the blower switch just below the radio only works on settings 4 and 5. The 1,2,3 settings do not work at all. Any ideas?
  • I am glad I found you guys!!!!!!!!!!!!

    I have a 2000 GP GT with 79k on it.

    I have been experiencing all the problems regarding the water leak (for a year or so) and the problems with the blower fan/resister board/daytime running lights.

    I shared this information with my mechanic, who was working his thru the problems to this.

    He's going to finish today, with the help of this info, and hopefully be able to keep the bill down a little.

    My car has had one other "sporadic" issue. The car would occasionally stall, typically during SLOW, RIGHT turns. I'm hoping that may be ignition related as well.
  • Just heard from mechanic, ignition wiring was the problem!

    THANK YOU!!!!!
  • bwies3bwies3 Posts: 1
    So I'm having the same issue with my '02 GP (fan doesn't work on 1-3/running lights don't work). Will the ignition wire solve both these issues? My mechanic is persistent in wanting to replace the blower motor. Is that necessary? Any idea on cost to repair the ignition wiring?

    Thanks in advance for the response
  • The ignition wires solved all problems with running lights and fan on all speeds < 5. I did not need a blower motor. Have them do the ignition wires first, then see. I don't think the cost was too much, I don't have my receipt with me.

    I printed off some of the earlier postings on this and showed them to the mechanic. They were amazed at the solution, they never thought the ignition wires would cause fan/running light issues, go figure.

    Hope it turns out well for you!
  • I had a question regarding a 1997 Pontiac Grand Prix. When my sister turns the fan switch on 1-4 dont work but five does. I heard that it is the relay switch. Also, her right window switch doesn't turn the window down and the radio display "freaks" out then returns to normal.

    Thank you, Jesse
  • christy10christy10 Posts: 19
    hay, i have the same problem with my 99 ,and if me a woman can fix it i'm sure you can, it isn't the relay or blower motor, it is ignition wiring , when you turn the car on and 1-3 doesnt work and makes running lights go off then it is that, it takes about 2 hours to fix it and about 100.00 in the part from advance auto, or might be more at other auto stores and you have to order it , it is not avaiable that day you go in , also they want a deposit also, it looks hard but really i did, my husband is happy that he married a woman that fixs cars. good luck email if you have and other question..
  • christy10christy10 Posts: 19
    hello, do you have any running lights and if they go off when you use 1-3 they it is the no relay switch is fine just change the ignition wires in steering column, because when you turn the key the wires send a signal to heater to work and if it is shorting out the it will short out other things, being a woman it took me 2 hours to change an about 100.00 in parts so i know that you can do it. good luck email me with other questions.
  • I was told that it was a relay switch, I would rather spend that to fix it than a 100 dollars.... does any one else have an opinion on this?

    Thank you; Jesse Cutler
  • what does being a woman have anything to do with it?
  • craig32craig32 Posts: 30
    When u say ignition wiring, can u be more specific (e.g., what 's the part name that you ordered)?
    Also, can u give a better idea what things (other parts) had to be removed to replace/instal this piece(s).
    Did you use any carbooks (which) to guide you/were u able to test the wiring w. a voltmeter, before u determined it was necc. to replace it?
  • fluxcapfluxcap Posts: 8
    Wow, I am so glad I found this site. This problem came up about 4 years ago. I searched and searched but could find nothing so I had the blower motor and resistor replaced with no luck. Then I just said screw it and lived with the problems. Well hot weather is here again and I need a fully functional a/c, so I figured I would search again. I'm getting a new ignition switch asap. I found another site that may be helpful to anyone else with this problem. It has a step by step (with pics) tutorial on accesing this switch. here it is Thanks again to everyone who has posted for helping me find a solution!
  • craig32craig32 Posts: 30
    I have heard that this part is likely responsible for our current problem, namely the air cond./heater fan sporadically working/not working (on ANY speed), but can someone tell me WHERE it's located (on a 2002 Grand Prix/3.litr)?

    And how do u change it without a repair manual (seems the shop manual,..150 plus bucks, all that's available)?!
  • craig32craig32 Posts: 30
    Can anyone furnish the details of HOW you even GET to the blower , or it's resistor, on a 2002 Grand Prix the person that posted that it waas just a matter of looking under the passenger dash was WRONG(!), as there's covering under there!
  • craig32craig32 Posts: 30
    You Can"t just look undeneath,....there a covering there (so how/which part do u remove??

    Also, what year was the car u were refering to, & where is the resistor (same side as blower?)??
  • craig32craig32 Posts: 30
    But, u didn't say for What Model/or year, this pertains to.
  • christy10christy10 Posts: 19
    i have a 1999 grand prix, my blower motor and resistor is on passager sider up in dash you have a panel that you might want to take down to see it, and resistor is hooked in front of blower fan, email me if you have other questions.
  • craig32craig32 Posts: 30
    Thank you, Christy! The more info i have on this the better.
    A picture someone gave me shows the blower clearly on the right side of the dash (under the passenger side, just near the middle dash), but, it shows , apparently, the resistor is on the other side ( the left of the middle of the dash, just to he drivers side of the 'middle dash'.
    Christy, is the resistor direclty mounted onto the blower motor of your vehicle (or is it separate?), and do you know if your 1999 GP, & our 2002 GP have the same configuration?
    As soo as I can, I'll put my 'blower breakdown chart' on this forum (it should help a LOT of people!).

    Also, i order of problems noticed:
    1)Pass power window stopped working 2 years ago (worked briefly after gettng new battery), and twice 3 mnths ago, other windows briefly failed).
    2)Power locks lock by themselves (when eneigne running, & person unlocks with drivers switch, then leaves car for a moment).
    3)Fan started intermittently not working on settings 1 & 2 (3, 4, & 5 ok), but then stopped working on all speeds.
    4)daytime running lights presently working intermittently (even when blower switch in off position).
    5)Rear defogger ha stopped working.

    All this, and NO windshield leaks have been noticed (yet).
  • christy10christy10 Posts: 19
    I have the same problems 3 , 4, 5, and it was the blower fan or resistor, it was the ignition switch. i went though the whole car changing everything blower motor, resistor and heater controls, and nothing work then i went on here and someone told me ignition switch wires, not the part with keys, taking the steering column apart change ignition wires switch, problems 3,4,5, started right away and still working great now. but the part has to be order and it cost me aboiut 100.00 and then you need special tools to use also.. you might want to think about this before you do the same thing i did change all things you think might be it and find out it isn't.. email me back...but it is up to you.. resistor has a plug that needs to be unplug before you take it out, and there is 3 screws that are very hard to get to, i found that blower motor out was easy to get resistor out..i hope this helps. also where are you from?
  • christy10christy10 Posts: 19

    try that website, it has pictures and that is how i changed mine also tells what tools to buy.
  • craig32craig32 Posts: 30
    Hi Christy (thanks for the messages, you're making the job less stressing!),

    I hope than it doesn;t turn out to be the ignition wiring(thank you for you providing that link/the step by step pics of how to install the new (ignition) wiring. It looks complicated (a repair manual would help/none for my model year exists yet,... that is x-cept for Pontiacs $130.00 'shop' manual trio), so i hope it doesn't end up being the wires.

    I am just about to try what may be a shortcut (around buying, or installing a new blower motor 1st (to see if that solves the problem), by 1st using jumper wires directly from a power source (the battery, if necc.), and connecting them directly to the blower motor. If it doesn't work, then i replace it, only then (i wonder if others thought of this before paying/installing parts,..sounds like no one did. I diddn't think of it immediately, either.). Always remember, u can test almost ANY electical parts on the car/else where, with jumper wires, as long as u know what you'e doing.

    If the blower works, then the problem is finding how to test the resistor (maybe then i would just buy 1,.. but plug it in without fully installing it, i can return it, if necc.).
    Have u dealt with dex-cool gaskets problems (am considering selling the car, before this happens)?

    I'm (originally) from San Francisco, Cal., but currently live in Fontana, Cal.
    Thanks Christy (and u are from,....?)!
  • christy10christy10 Posts: 19
    i had mine tested with diagnosis machine that is after putting blower motor in it and new resistor and it was ignition switch, the shop guy said that the ignition wires control everything with heater and lights and defroster also, so if all them don't work you might be changing something that you don't need to , it took me only 2 hours to change and being a woman i sure you can do it, my husband was happy he found someone that fixes cars because he don't know how.. i have a idea if you change ignition switch that will fix all your problem...
  • christy10christy10 Posts: 19
    hay resistor only cost about 25 -30 dollors and blower motor could be about 120.00 so what do you think you should do, i went an found a blower motor at a junk yard that work, they test them there... if you want jsut change resistor its the cheapest.. also im from pa and now i haven trouble with ford peace of cramp... it shots down while driving it and i bought a ignition modulor and fix that so i am pretty good with cars...
  • craig32craig32 Posts: 30
    I was thinking, that the only way i could imagine a problem with the ignition wiring beiing bad, & causeing multiple problems, would be if the wiring ha sbroken insulation, or had been made w. a defect (that lets 1 or mre wires eventually touch each other), or of the wires connections (or hrness connections) had/developed this defect.
    I bring this up, cause i;m going to examine like crazy (at least from the outside or harness end of the wiring, before I replace it/them (I saw a warning about being careful about the air bag system).
    Have u had any (other)probs. with your '99 Grand Prix?
    And do u know if the '02' model is similar to your (wiring wise)?
  • christy10christy10 Posts: 19
    my book for the car i have 99 goes to 2003 pontiacs so i think it might be the same.
  • christy10christy10 Posts: 19
    you can get a manuel online chilton just go to there website, or search online for another manuel.
  • craig32craig32 Posts: 30
    Great! Thanks Christy!
  • fluxcapfluxcap Posts: 8
    I'm not sure of the range of years that the ignition switch problem is found in, but my 97 had your exact same problems (fan not working on 1-4, daytime lights cutting off, no rear defroster) and fixing the ignition switch cured them all. It's not really the ignition swith wiring so you are not going to find any broken insulation or wires touching. The problem actually lies in the black box at the end of the wiring. This box has has six contacts inside it. These contacts become covered in carbon build up which reduces or completely stops current from passing through. That site website that christy10 posted is GOLD. I followed those directions a couple of weeks ago and fixed my problems. I didn't buy a new switch, instead I took the box apart and cleaned the contacts.
  • craig32craig32 Posts: 30
    Hi fluxcap,
    As with Chrity, every little bit helps(thanks for the info,'s GOLD, believe m!).
    1 thing, in my case, the instance of the blower not working on 1 &2/ & only working on settings 3, 4, & 5, was just 2-3 weeks. Then, blower failed completely (and intermittent problems w. lights/etc., began.

    I completely agree that, if it's easy, just cleaning the contacts in that box you described should be enough ,.....what did u use to clean them, by the way. I thought of using that 'electronics cleaner spray' that's at most auto stores, but, although it says 'leaves no residue, it leaves something that turns white, I wonder if that would interfere w. electrical conduction.
  • craig32craig32 Posts: 30
    Any problems w. dex-cool, like others (eating the gaskets? Also which ones/how much/at how many miles did the probs. start/, & do u still have the car?)

  • fluxcapfluxcap Posts: 8
    I just used some light sandpaper to clean the contacts on mine. The guy who made those instructions with the pictures on that page said that after a few years his problem came back, and instead of using sandpaper, he used the contact cleaner spray you are talking about. He said it did work. The good thing about trying the spray is that you don't have to take the black box completely apart. You only have to take the top cover off. For me, putting the middle section of the box back together was the hardest part (there is a spring in there that has to be put back in a specific position) and if you use the spray, you can avoid that step. This way you also don't have to remove the whole wiring unit, and can save some time.
  • craig32craig32 Posts: 30
    An Update!:

    I just found & unplugged the electrical connector to the blower, tested, & found that it IS getting around 12 volts on all settings of the blower switch (my meter showed 11.91-11.97 vlts.).

    Also, i plugged the plug back into the blower (with the ignition switch o run, still, e.g., power on), was preparing to leave, when (after about 1 minute), what do ya know, the blower starts blowing! It was randomly left on setting #5, & when I switched to another setting, it went off (& stayed off,.....even after i tried setting 5 again).

    For many of you that mentioned water leaks harming your blower, i did notice dried water spots, but on the opposite side of the connector (didn't see where the resistor was).

    Anybody have any opinions. My best guess is that the blower probably has a short in it, and to go to a junkyard & get a replacement. (this assumes there is no such thing as a load/no load reading factor in the 12 volts i rad, when it comes to heavy load things, like blowers!).

    Also, anybody know what that 'cooling hose connected to the blower work (maybe it got clogged at the other end, & blew the blower)?
  • fluxcapfluxcap Posts: 8
    Sorry, I meant to mention this earlier, when you were talking about hooking up test wires for the blower. I did the exact same thing you described. I unplugged the blower and resistor and checked each one separately. When the blower fan was NOT attached, I got perfect 12v readings from the resistor wiring. But as soon as I hooked up the fan, it would die. I tried all kinds of electrical riggings attemping to diagnose the problem, and found nothing. I know you really don't want to replace/fix that switch, but I'm 99.9% sure that is your problem.
  • craig32craig32 Posts: 30
    Thanks for the info.
    I guess what I'll do is get a solid power source, & use jumper wires from it, & hook them to the blower directly (while it's still in the car), & see what happens.
    That way, if it's as in your situation, i wouldn't have done much work.

    2 things; what year is your car, & (just in case), where was the resistor located (on what side, angle, etc. Also, is it attached to the blower ,...i can't find it?

    I want to eliminate that too, before I'm faced w. the bad news (of ultimately changing the switch/wiring).
  • fluxcapfluxcap Posts: 8
    My car is a 97. The blower fan and resitor are located under the passenger side dash (above where the passengers feet would be). You'll have to remove a felt/carpeted cover which should be attached by two black plastic push clips (similar to the plastic clips that hold your interior door covers in place) You can see the fan in the picture below. The resistor is located behind the fan. You'll need to remove the fan first (easy) then the resistor (not so easy). The resistor has three screws. One is on the front side and easy to get to, the other 2 are on the backside and almost impossible to reach. I removed just the front screw and then just wiggled and yanked the resistor loose from the other two. Good Luck!
  • craig32craig32 Posts: 30
    Thanks for the picture (That's HOT!!!).

    It looks ominisly identical to the '02 model, which surprises me (also that Pontiac hasn't fixed the successive problems.).

    How did you deal w. that thick/solid hose full of wiring across the blower (on mine, it's more cramped for space, as you'll note in the pic there's nothing to the right of the blower,...)?

    Did you use any specialty tools w. the blower or resistor removals?

    How many miles did you have when your blower gave out totally?
  • fluxcapfluxcap Posts: 8
    No special tools needed. Just a socket wrench set and a short extension. The big hose of wiring wasn't a problem. It's pretty solid, but it will allow enough play to easily get the blower out. My problems occured about 4 year's ago somewhere around 90,000 miles. At that time, no website forums were talking about the ignition problem so I took it to the dealership. They replaced the fan and blower with no luck. Said they could keep testing, but their hourly rate wasn't cheap, and I was a broke college student. I went without a/c and heat for four years! This year I decided to do more research and found internet talk about the ignition switch. Ahh the internet!
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