: 87 brougham ac fan misbehavior



darekk
04-03-09, 12:06 PM
Gosh, forum system logged me off while submitting thread. So I'll have to put it all in all over again. :hmm:

Anyways, as you might have seen, I've just introduced my '87 Brougham to this forum in a separate thread.
http://images40.fotosik.pl/83/c703c5fa81ebb750med.jpg
http://images49.fotosik.pl/87/1c0c05c9a5b444a6med.jpg

This car is in immaculate shape, as expected with this milage.

There is however a small issue that showed up which makes the ownership experience 99 instead of 100. It's an awkward behavior of a/c fan.

As you can see on the picture below, car is equipped with automated climate control.
http://images46.fotosik.pl/97/4a126dd89e9029ccmed.jpg
It operates in 4 basic modes:
1. Econo - no compressor, all functions automatic incl. fan
2. Auto - compressor on, all functions automatic incl. fan
3. Low - compressor on - low fan speed
4. High - compresson on - high fan speed (but not max)

It all worked fine until recently. Now when I start the car or engage any of the operating modes I will hear all those flaps closing or opening to redirect air where needed. Compressor clutch engages. But fan does not. It stays quiet and no air flows through.

I thought fan is dead. But it's not! I accidentally found that all I need to do is to make it move by giving it a max power (max speed) impulse. I can do that by pressing windshield defrost mode (max fan speed) or by lowering temp setting to absolute minimum (again - max fan speed). This is sufficient to start the fan. One second is enough to make it work. Then I can go back to any mode that I wish for and it will work just fine. No probs. Until I switch it off (a/c or a car). Then switching it back on requires same "starting" - max speed for a second, then use any mode I wish for and it will work just fine. I think it also happened once, that while working system set the fan to a lowest speed setting (temp might have been just right) and it stalled or just stopped turning. I had to start it again by lowering temp to minimum for a second.

What can it be? I am totally lost. I thought that fan is stalling, is stuck or something and needs max power to start moving. Or maybe it's a fuse somewhere? Not a clue.

I've had similar problem in other car - fan would operate only in highest speed - but that was a manual climate car. And the problem was solved by replacement of fuse.

jayoldschool
04-03-09, 01:54 PM
Likely the programmer board (the part that controls the HVAC). I will check the trouble flowchart for you in my FSM and let you know tonight from home what the factory says to do...

darekk
04-03-09, 04:21 PM
Likely the programmer board (the part that controls the HVAC). I will check the trouble flowchart for you in my FSM and let you know tonight from home what the factory says to do...

thanks,

gosh - hope it's fixable
and not costing thousands of greenbacks

Aron9000
04-03-09, 05:01 PM
thanks,

gosh - hope it's fixable
and not costing thousands of greenbacks

It might be the climate control computer. You can get another one from a junkyard and see if it works, should be the same from 86-89 model years.

jayoldschool
04-03-09, 05:33 PM
This is the progammer (also known as the "climate control computer"):
Programmer (http://info.rockauto.com/SMP/SMPDetail3.html?PRG1.html)

rockauto.com has them, and you can likely get it locally as well. Used would be ok if you get an exchange warranty.

1987 CADILLAC BROUGHAM 5.0L 307cid V8 (9) : Electrical : Climate Control Computer Price Core Total Advice
STANDARD MOTOR PRODUCTS Part # PRG1 More Info {remanufactured}
Programmer; OE: 16028106
Choose:
* Non-stock item--shipping delayed up to 2 business days

Part Image
$95.79 $0.00 $95.79
Add to Cart
STANDARD MOTOR PRODUCTS Part # PRG12
Programmer; OE: 1227275
* Non-stock item--shipping delayed up to 2 business days

$168.79 $60.00 $228.79

sven914
04-04-09, 06:31 PM
Someone may refute this but, what you described sounds like normal operation.

The ECC takes inputs from an exterior temperature sensor and an interior temperature sensor. If you have the ECC set for 70 and the outside air temp is 30 and the in-cabin temp is 60, then the fans will come on at low speed. If you put your hand by the heater vent on the floor, you should feel some warm air flowing from the vent. Hitting the defroster button tricks the ECC into giving you high fan speed.

If the engine is cold and the outside air temp is cold, then the ECC will not turn on the fans until the engine reaches operating temperature. If the ECC's interior sensor reads a significant increase or decrease in cabin temperature, then it will command the fan speed to increase or decrease based on the temperature setting. If the in-cabin temp reaches the commanded temperature, then the fans will stop.

In the winter I have to do the same thing with my car, to get warm air circulating through the interior faster.

jayoldschool
04-04-09, 10:03 PM
I took it to mean that the fan never operates if he leaves it on AUTO.

Darekk, have you tried to turn the heat up, with it on AUTO after you start it? If you leave it on AUTO, does the fan come on eventually? It may take a few minutes. If it does come on, all is working fine.

darekk
04-06-09, 10:43 AM
I took it to mean that the fan never operates if he leaves it on AUTO.

Darekk, have you tried to turn the heat up, with it on AUTO after you start it? If you leave it on AUTO, does the fan come on eventually? It may take a few minutes. If it does come on, all is working fine.


let me try to do that :)
do you mean to turn it up to max or just leave it at say 75?

btw: last night when i switched it off and switched it on again it worked just fine

gosh - this time i hope that i made a fool of myself and everything is just ok

:thepan:

darek

jayoldschool
04-06-09, 11:16 AM
do you mean to turn it up to max or just leave it at say 75?

Start the car. Press AUTO on the HVAC. Press WARMER on the temp. Put it up to 75. Start driving around. Within a few minutes, the fan should start blowing warm air out the bottom floor vent. After a few more minutes when the inside of the car is nice and warm, press COOLER and turn it down to 70. The fan should soon slow down (if it was operating at a higher speed).

Keep us posted.