89 Fleetwood Lost Dash Blower On

[Ahabiam]

Hi - I am a newbee to the forum.
This is a 1989 Cadillac Fleetwood. V8 - Front Wheel Drive, and all the bells and whistles. A few weeks ago I noticed an electrical burning stench. I spent some time on it, but could not locate anything obvious. A few weeks later, the Check Engine Light is on, the digital dash is half dead - the Speedo works, the A/C-Heat controls and the Fuel gauge - have what looks like a sideways "C" displayed - more like a "U" I suppose. The blower motor is on high - all the time - when the car is running. It is purring away, runs good, but something is fried. I have been checking around, I saw one post reccomend pulling each dash item to see which is shorted, I saw another stating the Fuel Sending Unit was bad, and I saw a third instructing to remove and replace the Body Control Module.
What do the experts suggest?

[maxwedge]

Sounds like the contol head or cluster shorted, these units would have to be removed for inspection, look at the harnesses also.

[ronaldk]

I have same car. My blower motor also same problem.But I dont remember my dash. The blower controler is mounted on firewall somewhat on passenger side as I recall.Its a pain to get out that I remember. This is a large IC I dont know cost but am pretty sure its dealer only part, I got mine from friend who owns bone yard. I will look tommorow under hood cause I could give you exact location and wires I removed to stop blower which I could not shut when veh was running.

[ronaldk]

Ok I took a look and there is a plastic shield from passenger firewall to a little past center firewall that needs to be removed (two or 3 screws), then you can access wires and module that is mounted inside. I believe 3 screws if I remember and unit can be pulled out. Your a/c lines are there also making it hard to access. The car I took unit from in bone yard was seville and I had to bend those a/c lines out of way to get assembly out.

[maxwedge]

Called the blower power module.

[Ahabiam]

Hey everybody,

Thanks to all for the tips. I found that the BCM was bad. It turns out that the Body Control Module sends the variable voltage to the blower motor, and also coordintates the fuel panel, gas gauge, and A/C - Heat temp controls. It is located behind the dashboard, and mounted sideways/horizontal above the mixing box and below the heater core/evaporator assembly. Some teardown required of the interior to replace it. I found a module for a little over 100 bucks, with a core charge of 30. You also need to swap over the control chip, and the new unit comes with a cheesy tool to do so. Reset the codes afterwards, and everything is back on line. Digital dash is all back, blower control is back, and A/C working. I read on a post that usually something causes these to blow out, but since this is an 89, with over 170K on the original BCU, I am hoping it was just old age. We will see. Thanks Again.

[ronaldk]

Thanks for posting back. As I said I did not remember if my dash had problems, I think only the blower stayed on. So in future remember where that module is and I will remember your module location since that has yet to happen to me.

[EDarcy]

Thanks to all for the tips.

[Tech II]

EDarcy, if you have the same problem, be aware of this.....

I don't know if an '89 Caddy had a Body Control Module OR a blower control module......one of them varies the voltage to the blower motor....and when they go bad, they cause the blower motor to run even with the key out of the ignition, causing dead batteries......

I doubt you can even find either part(unless it is used).....I will say this, if you replace this part, the smart thing to do is also replace the blower motor, which can take out the BCM/bcm......if you don't, it can happen again to the new/used part you replaced.....