94 APV 3.8-No heat, no air...nothin'-HELP

[apvtrvlr]

Hi, could really use some help. My 94 APV only has 60K actual miles on it, runs great, etc.

It's winter here and the heater starting acting odd over the last week. Sometimes it would work, other times not. When working seemed that amount of air coming out of vents was "oscillating" more/less a bit. 3 days ago heat just stopped working period...although after driving for a bit and coming up to temp I can still feel some hot air seeping from top vents very slightly. Also, one time I started up and heat was rocking from the defrost. Parked at the store, came back out and nothin' again and hasn't worked at all again since.

So far I've read every post on this forum with any sign of similar issues. I checked the fuses and the low speed relay under dash (swapped with horn relay-still nothin'). Looked for vacuum leaks/cracks and everything seems fine. Radiator is full of coolant to neck and no noticeable coolant leaks anywhere.

BTW...A/C does not work now either. Just this summer I recharged A/C and had icy cold air all summer. Heat has always blown hot and steady via vents, defrost, wherever until this stuff happened.

I'm no mechanic by any stretch but am capable of most basic stuff and willing to try. I guess what has me most confused is what would affect both heat and A/C like this all at once when both were just working fine?

No leaks from heater core inside and when it was last working the flap was opening and closing. The main computer was replaced about 1 year ago but otherwise there's been no problems anywhere and just normal maintenance.

Can someone take me through a logical path of things to check? Could this be blower motor resistor or blower motor high speed relay? How do I test these if so? Should I just replace them?

Also, what is the "blower/heater switch" and where is it located? I saw this on autozone site but no useful info other than saying it can make things not work, including A/C compressor clutch (which also doesn't appear to be engaging/disengaging with A/C on or not, BTW).

Thanks very much for any and all help you guys can offer!

Bob

[hmmpepsi]

Bob, I have a 1990 lumina apv. I had the same problem twice now. Replace the Blower motor. It is attached to the fire wall. Open hood and it is next to the windshield wiper motor on the drivers side. removed the air cleaner assembly. You may have to remove the left side windshield wiper arm linkage. I am pretty sure that you do. You may be able to use the old fan. Sometimes the fan is to brittle and you may break it upon removal. I would recommend purchasing the dealers blower motor, it comes as an assembly motor and blower. autozone and checket only sells the motor but, your fan may break.
If you already check all fuses and realay then I am pretty sure its the motor. I replace mine twice now, but my lumina is 19 years old.

[LMP]

ALl current to the blower motor passes through the high speed relay through normally open and through normally closed contacts for low speeds. http://www.avigex.ca/xport/hvac_diagram_front.jpg
BUt best of all, disconnect motor and feed 12V direct to the motor to test it. If if runs, then go for the high speed relay. IF high speed has been used for long stretches of time, either the relay or the socket may have melted.

[apvtrvlr]

Originally Posted by hmmpepsi

Bob, I have a 1990 lumina apv. I had the same problem twice now. Replace the Blower motor....

Thanks very much for your help and feedback!

[apvtrvlr]

Originally Posted by LMP

ALl current to the blower motor passes through the high speed relay through normally open and through normally closed contacts for low speeds. http://www.avigex.ca/xport/hvac_diagram_front.jpg
BUt best of all, disconnect motor and feed 12V direct to the motor to test it. If if runs, then go for the high speed relay. IF high speed has been used for long stretches of time, either the relay or the socket may have melted.

Thanks. I know for sure the high setting has rarely been used and the relay and socket visually appear to be in very good shape.

Now, for a probably lame question about doing this...to connect 12V directly to blower motor I assume the reddish wire/tab in the connector(top) is hot and the black (bottom) is ground, correct?

Do I just run a piece of wire from the pos batt terminal to the hot tab and then another wire from something well grounded to the ground...or use the neg batt term for that? Or, is there something else nearby I should connect to motor from?

Thank you

[LMP]

THere is a positive post on the firewall with a red plastic cover near the power brake booster, so no need to go to the actual battery. Run a jumper from there. ANd yes, any good ground anywhere on engine block will do for the negative. Keeping the right polarity (Red positive, black negative) has the only efect of having the motor rotate in the right direction.
..by hte way, I suppose the HTR/AC 25 amps fuse has been checked....right?
www.avigex.ca/xport/fusepanel38.jpg

[apvtrvlr]

Originally Posted by LMP

THere is a positive post on the firewall with a red plastic cover near the power brake booster, so no need to go to the actual battery. Run a jumper from there. ANd yes, any good ground anywhere on engine block will do for the negative. Keeping the right polarity (Red positive, black negative) has the only efect of having the motor rotate in the right direction.
..by hte way, I suppose the HTR/AC 25 amps fuse has been checked....right?
www.avigex.ca/xport/fusepanel38.jpg

Got it...thought of that other positive lead after my post. Yes...all fuses checked.

Turned out to be the blower motor...everything fixed and working beautifully now.

Went ahead checked out pretty much every aspect of heating/cooling sys. so I fell like I somewhat understand how everything works in case of later probs.

Wouldn't have know where to start with this nor could I have imagined doing it myself without the help of everyone who posted here...thanks very much to each of you! I'm sure you saved me a bundle versus taking it into a shop.

Bob