Heater fan switch? Or Relay problem?

It's been awhile so I am posting this as new but with new info. Cold AM below 20 deg. fan won't come on any setting. Start turning it back an forth several times and it comes on in high mode...I leave it there get to my destination, leave switch in high positiong and turn car off. four hrs pass I start car and fan is on high just fine....car gets warmed up and I turn it down to any lower setting and fan shuts off...cant get it to come back on at all. Get to destination put switch on high (doesn't come on) turn car off. 1 hr later I start the car the fan comes on in high.....I go home and remain puzzled, any ideas on this are welcome. I am thinking relay or switch, but neither really makes sense to me....

Here`s what my blower motor does. Most of the time it works fine except about once or twice a week. Turn the fan on, nothing happens. I`ve taken the access panel off under the glove compartment and slightly tapped the blower motor with my hand and then it comes on. Had a dealership tell me originally it was the heater control head ($443) and the the blower motor resistor ($233) to install them. I left (never to go back again) and found out it works fine after I bump it. Going to buy another blower motor on Ebay or a salvage, might spend $50 at the most, dealer wants $252 for the blower motor. I was told it might be just a bad contact point in the motor itself.

Don`t know if this will help, but might give it a try. :grinyes:

Right, I don't have much confidence in my dealer as well, sorry thing to say I guess but then they don't think they are the problem.
I am going to wait for warmer weather to get at this, way too cold for me, seems to be stuck on high for now. Though it does just quit at times. Probably built by Delphi which has always had quality issues with switches. I did a search and found other posts on this and seems to be popular source of frustration. Hey isn't GM in a bit of trouble?

Got a few questions if any would like to answer up please do so...First the fan quit working at all today so I sropped and talked to a couple of mechs that have worked on this type thing before and this is what they told me. If the fan works on high only it means the resistor relay is bad....if it does not work at all it is probably the electrical component attached to the ignition switch that has failed....does this sound right to you?? So if any of you know and can explain how to access underdash areas (how to take the covers off for one) and two...how to remove the ignition switch...going to library to see if a repair manual has any of this info but I have my doubts so I could use a little help on this.

what year is your Impala? I can help you figure it out...I have seen several like this...

2002 base model, non dual climate control, ign in dash...under dash covers seem to have a plastic release but don't want to break them in the cold weather trying to get them out of the way. Library closed till Sat. AM. pretty sure all they have is wire diagram and not part explosion dia. As I understand it the lock cylinder and electric switching module are separable and the latter is the replacement piece that is defective. but I will circuit test w/volt meter first if possible.

2002 base model, non dual climate control, ign in dash...under dash covers seem to have a plastic release but don't want to break them in the cold weather trying to get them out of the way. Library closed till Sat. AM. pretty sure all they have is wire diagram and not part explosion dia. As I understand it the lock cylinder and electric switching module are separable and the latter is the replacement piece that is defective. but I will circuit test w/volt meter first if possible.

if you hit blower motor and it starts to run it is the brushes that are worn.... if you are going to keep car get new motor and before buying get meter and if voltage is at motor and connector to motor is clean and secure motor has worn brushes just like starter or fuel pump....sometimes you can't get it to work and a hit gets it to go......

Yeah, I get that...problem is I can't get the insullator panal to come off and don't want to break it. 2 squease clips won't release and I haven't quite got that figured out. (how they work) No instruction on that in the books I picked up....

Yeah, I get that...problem is I can't get the insullator panal to come off and don't want to break it. 2 squease clips won't release and I haven't quite got that figured out. (how they work) No instruction on that in the books I picked up....

is this the panel for access to motor...?

Yeah, I get that...problem is I can't get the insullator panal to come off and don't want to break it. 2 squease clips won't release and I haven't quite got that figured out. (how they work) No instruction on that in the books I picked up....


Should be able to push on the clips and and work the panel free. My son-in-law did it in a couple of seconds (didn`t break the clips either). There is a tool for those clips also at the auto parts stores.

Here`s a neat page on accessing the dash:
http://impalahq.naioa.com/HowTo/Dash.html

Got a few questions if any would like to answer up please do so...First the fan quit working at all today so I sropped and talked to a couple of mechs that have worked on this type thing before and this is what they told me. If the fan works on high only it means the resistor relay is bad....if it does not work at all it is probably the electrical component attached to the ignition switch that has failed....does this sound right to you?? So if any of you know and can explain how to access underdash areas (how to take the covers off for one) and two...how to remove the ignition switch...going to library to see if a repair manual has any of this info but I have my doubts so I could use a little help on this.

57chevy,

I'd be almost certain that your blower motor resistor is bad. Why? Because your fan did work on high, but not on other speeds. The resistor simply limits the amperage that can go to the blower thus decreasing the actual speed. On high, current does not flow through the resistor, rather straight to the fan. However, many resistors have a relay built into the unit so it could cause outright failure. Do you have access to wiring diagrams? Let me know if I can help.

In answer to the two questions posted J cat: yes this cover needs to be removed for access to the motor and resistor...Kemi: no, wire diagrams I have do not include this system, only instument panel...dh 271: thanks for the link at least tells me I am on the right track pushing on the clips. I'll repost shortly after I try again...Thanks all"

[quote=Kemi]57chevy,

I'd be almost certain that your blower motor resistor is bad. Why? Because your fan did work on high, but not on other speeds. quote]

the original first post stated that the blower did not work at any speed I have troubleshot many of these and its usually the motor brushes worn or corroded connectors......... ...

Well I did get a chance to try again got one of the clips to release but not the other...forward of the inner clip is a push pin type retainer which as I understand takes a special tool (door panel puller). Why the other clip won't come loose is somewhat a puzzle...I'll try again tomorrow, fan is working on high sometimes and sometimes not...so it may be the resistor or corroded connector, just need to gain access first to test out...Thanks all for the input here....

Well I did get a chance to try again got one of the clips to release but not the other...forward of the inner clip is a push pin type retainer which as I understand takes a special tool (door panel puller). Why the other clip won't come loose is somewhat a puzzle...I'll try again tomorrow, fan is working on high sometimes and sometimes not...so it may be the resistor or corroded connector, just need to gain access first to test out...Thanks all for the input here....


to get the panel to release use dish soap mixed with water in a spray bottle this will safely lube joints to ease removal.......

I'll give that a try j cAT, I keep a solution handy for air leaks (Tires & natural gas).

OK, got the panel off...had to go buy a few tools 1/4 swivel for one...I think I am going to take the fan motor down as well for easier access and full inspection. May be a water leak to consider foam on bottom of fan motor was damp. windshield (has been replaced) or body seam. I'll post what I find.

OK, got the panel off...had to go buy a few tools 1/4 swivel for one...I think I am going to take the fan motor down as well for easier access and full inspection. May be a water leak to consider foam on bottom of fan motor was damp. windshield (has been replaced) or body seam. I'll post what I find.

this could be the issue water causing failure..... if this is the case fix leak before new motor.......

this could be the issue water causing failure..... if this is the case fix leak before new motor.......
Yeah I'll have to find that for sure..pretty cold here and no warm area for working it out, going to put this off for a while till warmer weather enables me to do leak testing. So far last 2 days it's been working on high pretty steady ( NO CUT OUT). Hope to get some warming trend next week and I know how hard it is find leaks you often see the results but not the cause..I'll need some time on this project.

the original first post stated that the blower did not work at any speed I have troubleshot many of these and its usually the motor brushes worn or corroded connectors......... ...

Right, but the fan is sometimes working on high speeds. It will not work at all on any of the lower speeds. That usually means the resistor. At high speed, the resistor is not needed, which is why the fan will work. Sometimes, GM builds the relay into the resistor which would explain why it will intermittently not work on high. Of course, the motor could also be bad. I'll check my repair source.

57chevy,

I checked your blower circuit, and the resistor includes the relay for the circuit.

Orange wire #1 = Power to relay
Orange wire #2 = High speed from switch
Black wire/s = Ground
Yellow = Low speed input
Tan = medium one input
Light blue = medium two input
Purple = medium three

Let me know if I can help any further.

Kemi, thanks for the look up....I knew that from the replacement resistor I purchased that the relay is built in. Actually it's a combo of three resistors in a circuit. I just have to wait for a warmer day to do the leak check, no sense replacing part till I discover the main cause of failure if it is a water leak. It definately was not antifreeze and don't think it could be condensation. I just can't deal with the cold like I used to or I would be out there working on it now. Yes I know you were responding to a post by j cAT in your previous post and I do appreciate all input. Thanks to all ya'll....!

[quote=57chevyragtop] no sense replacing part till I discover the main cause of failure if it is a water leak. It definately was not antifreeze and don't think it could be condensation. I just can't deal with the cold like I used to or I would quote]

If this was not antifreeze then the most likely explaination is the condenser air box drain hole is plugged.... as water snow or condensate from a/c collect in box this drain removes moisture so clean out the drain hole and bottom of air box from debris......

Kemi, thanks for the look up....I knew that from the replacement resistor I purchased that the relay is built in. Actually it's a combo of three resistors in a circuit. I just have to wait for a warmer day to do the leak check, no sense replacing part till I discover the main cause of failure if it is a water leak. It definately was not antifreeze and don't think it could be condensation. I just can't deal with the cold like I used to or I would be out there working on it now. Yes I know you were responding to a post by j cAT in your previous post and I do appreciate all input. Thanks to all ya'll....!

You're welcome. If you need help for further electrical diagnostic just ask. I do believe the resistor is bad. But like I said earlier, there may be more than one problem. And Jcat is right. Definitely check the motor. Could be a water leak and/or an intermittently failing motor. I've seen both before. Good luck and post more if you need more help. Plenty of good people here.

57chevy,

One more thing. Don't necessarily rule the resistor out as the 'main cause'. For instance, don't think that another part would have to 'ruin' the resistor. They go bad on their own. In fact, it's somewhat of a chronic problem for GM. They have several recalls and TSB's about this. Several 'enhanced designs' and 'replacement styles' for this part. Good luck.

Yeah , I go along with the plugged drain theory-- GM W-cars are the only GM vehicle to use a "nipple" on the end of the drain plug rubber elbow tube-- all othe vehicles use a regular elbow- wide open at both ends- but W-car uses a nipple on the end- to reduce air losses out that hole- but it plugs rather easily-- you can access this elbow from engine side of firewall- with your left hand- in center of firewall in the recessed area - standing on passenger side- looking forward- and feel for the elbow- pull it off and see if it is plugged- I had a W-car once put a gallon of water on the floor when I pulled off the elbow- I also have seen W-cars "process" that water like a blender when turning hard left- blows the water out the vents even--

If this is the case- trim the nipple off the end of the elbow tube- and be sure to put the elbow tube back on- if you don't then there is another scenario brewing- the water will not drain out at highway speeds- and after an hour of non-stop driving the water comes out onto the floorboard- due to air pressure not letting the water flow out the drain- the elbow creates the "chimney effect" to draw the water out at highway speeds......good idea to check yours- I trim every W-car I get in- just for future problem avoidance.....

Wow! I am totally amazed at the helpful responses and the thoroughness of details by all of you. Thanks so much, I will check that drain hose at the first opportunity to do so. I will be a bit busy the next few days with some other business, but be assured of my appreciation till I can return and post. dave

Wow! I am totally amazed at the helpful responses and the thoroughness of details by all of you. Thanks so much, I will check that drain hose at the first opportunity to do so. I will be a bit busy the next few days with some other business, but be assured of my appreciation till I can return and post. dave

no problem thats what these forums are for help people, save money.... I f you have removed blower motor just hook it up to 12volts to see if it runs properly and while running give it a few hits to see it it cuts out,,,,,

Hey guys, It's been a hard 4 weeks weather and injury wise. I was able to attack the leak problem today and here is what I found: The rubber body gasket below windshield and cowl had come off or was not put on securely after windshielad replacement...the cabin filter was soaked as a result water was also getting to fan motor and resistor pack. Bought a new filter, cleaned and secured body gasket. Have not yet installed the resistor pack due to injury still healing (fell hard in the snow couple of weeks ago). Thought you would like an update on this. I will post when I am able to get to the other part of repair I am figuring two weeks more healing. Thanks again for all your input, it has been of help....little dave!

Fixed! managed to get to this work today. removed and renstalled same fan, while fan was out I replaced the resistor pack with a new one. Getting this out was the most difficult part, only one screw needs to be removed the 2 closest to the firewall just need a few turns as the pack has 2 slotted screw U-shaped openings on that side. used 1/4 drive w/universal+5/32 deepwell socket...a short 1/4 wabble extension would work with the deepwell too but I couldn't find one....All works well now, Thanks again all....dave