Blower under the dash no worky (1 Viewer)

[Riad]

Driving home from work, all of a sudden I hear this little flapping noise coming form under the dash. I had the blower on (not the AC) with heat set to 75 degree. Then the blower fan stops working. The vent (or the Fresh/Recirc) won't close and the the AC doesn't work either. The Auto button has a very dim light. Checked the fuses; they all look good.

Any idea any one?

Thanks

 

[azrider]

did you take the cover and fan all the way out? I too heard the flapping noise(no problem with anything not working)and I took the cover and fan assembly out and there was a plastic wrapper that got sucked in there causing the noise. May be the same for you.

 

[Riad]

I haven't started on taking things apart yet; wanted to see first what the others had experienced. I am little confused about the malfunctioning dash buttons (Auto and AC). All the buttons from Lo to HI light up but the fan doesn't come on. The Auto button lights up with the yellowish light with the head lights on but doesn't go green after being pressed. The AC button has no lights (Green/Yellow) with the head lights on. Sounds like some electrical gremlin has invaded

Thanks

 

[Riad]

Looks like all three buttons (AC, AUTO, Fresh/Recirc) are not working. FSM says I've got problems with the one/all of followings:

• Heater main relay
• Blower motor
• Blower resistor
• Blower speed control switch

Funny thing is my rear heater blower works fine.
this s*** seem more hairy then I thought

 

[Tools R Us]

Sounds like what mine did, was the relay. I pulled it, popped the cap off and cleaned the contacts with some very fine wet-dry sandpaper. Was going to order a new one, but forgot about it, been a couple of years and working great.

 

[Riad]

Sounds like what mine did, was the relay. I pulled it, popped the cap off and cleaned the contacts with some very fine wet-dry sandpaper. Was going to order a new one, but forgot about it, been a couple of years and working great.

Is this the heater main relay? Where is it in the truck? I have been looking for it for past 3.5 hours and can't find it

 

[Tools R Us]

Is this the heater main relay? Where is it in the truck? I have been looking for it for past 3.5 hours and can't find it

Behind the driver side kick panel.

 

[Riad]

Thanks! I think I was looking in page AC-88 which only has the relay picture. Gonna try to tackle it tonight. The rear heater no longer working now. All lights illuminate though.

 

[fowldarr]

Did you try kicking it? I have a 94 Yukon (I know, I know, but I have to drive something while my 60 is under construction, and I'm still kicking myself for letting my wife sell the 80) anyway the point is, the fan/blower doesn't always work in the yuk but if you give it a good solid kick it fires right up. (Domestic engineering)

 

[Tools R Us]

Thanks! I think I was looking in page AC-88 which only has the relay picture. Gonna try to tackle it tonight. The rear heater no longer working now. All lights illuminate though.

IIRC the rear uses it's own relay, you may have a problem in the power supply circuit?

 

[Riad]

IIRC the rear uses it's own relay, you may have a problem in the power supply circuit?

Joy!! Where do i start to trouble shoot that? I think I heard a "pop" or "clack" noise coming from under the dash/glove box when pressed the rear heater switch. I was driving while doing this.

 

[BtCruiser]

Check the fuse again!! I just did this two weeks ago and even bought a new motor. That fuse has a little cooper strip that will start to green up and then the current doesnt go through it anymore. Then NO motor!! I spent hours on this!!!

 

[BtCruiser]

2.96 at the auto parts store!

 

[Tools R Us]

I have never had a rear heat problem, but IIRC they are a totality separate deal, run off of their own fuse, etc, so the two failures probably aren't related?

 

[Riad]

Turns out I was wrong about the rear heater. That works fine. With the truck running at 60 mph I guess I wasn't hearing it. This crap is playing tricks on me now . Yeah I know they have two different relays. The rear heater fuse (20 amp yellow) looks fine. Is there a front heater fuse some where? I thought that doesn't exist. What is this FLHeater 40 amp fuse (or small white head relay)? I thought that is for the small circuit is it not?

 

[Riad]

Tested the heater relay for continuity: Pins 2-4 and 3-5 seem to be OK. I guess the next stop would be the switches. Oh well.. I've got my work cut out for the weekend

 

[alia176]

Dude,

You having some bad Cruza Karma or what? Repent, repent....

 

[Riad]

Yeah, I might be having some of that cruza karma . Usually around this time of there year I deal with this sorts of karmas; last year I was finishing up my HG .

But I think (hope) I have narrowed it down to the culprit and it is some where in the dash heater control unit; the "AUTO" switch to be more specific. I think I am gonna try to figure out a way to eliminate that switch by putting a blank or some thing in there; once I determine that the switch is the issue. I have been thinking about what Tools said about the power supply circuit issue. IIRC the AUTO switch dictates control for the AC and Fresh/Recirc switches. None of these switches illuminates but all the others do when the lights are on. Since the Fresh/Recirc button is stuck on "Fresh" and the temp control is stuck on 75+ degree, I get hot air coming in through the vents during driving once the truck is warmed up. It is getting to low 20s these days. Thank god it's not summer time and I can afford to procrastinate . So the plan is (has been for past few days) to pull the Heater control unit and the three switches and test them. Then test the power supply in that row of three connectors. I know I am low on freon but I don't see how that would contribute to having no power on those three switches.

Wish me luck

 

[Riad]

Need some help here guys .

First of all, I feel like a real dumb ass . I thought those switches were individual switches and I could just replace the one that is bad. . The whole heater/ac control unit is a module and ofcourse the switches are all integrated in there. I have also found out that there's a switch on the back of the heater control unit that allows to switch between AUTO and MANUAL (picture below). Can't find any reference in service bulletin of this but after I switched that switch to manual, my Fresh/Recirc light came back but it won't change to Recirc mode once pressed. Still no light on AC and AUTO switches.

Also took out the blower motor. I hooked up my multimeter '+' and '-' connectors with the connectors for the blower then turned on the ignition. I get only up to ~4.5 volts from there . No change on the volt once any of the blower speed switches are pressed. I thought that wire gets 12v.

Thanks for your input

 

[Riad]

Ruling out the the motor (fan).