My fan is blowing on maximum speed at all times, as long as the battery and wires to the motor are connected. Yesterday, I tried to find the relay that feeds the blower motor, but it seemed impossible. The wire to the relay is purple, and that wire wasn't hard to find, but I'd like to knowthe position of the relay.
Is it under the fuses under the hood, or under the panel in front of the passenger's knees? Or even in the trunk or somewhere else?


I sure hope someone on this forum knows where to find the relay, and if not, I just don't know what to do. I don't want to reassemble any more parts if I don't know it is needed to find the relay.

It depends on your Vin # of your engine for a 91 park.
If you mean the radiator fan then its proubably up on the main relay fuse under the hood at the top center of the firewall with big relalys and fuses. There is high speed relays and low speed coolant blower relays there so you will need to pull them to see which one is turning the fan on.
They are easy to pull once the cover panel is removed. The box type plug-ins are relays or circuit breakers.

Hopefully it's the relay, and not something else like the temp sensor or the PCM turning them on.


Edited by: bassasasin

The fan is the one that blows air into the vehicle, not the one in the front of the car. I tried to remove every one of the relays under the hood, but no one seemed to have the right colors (with purple as the most important one).


From the motor I can follow the purple wire, and it disappears in a plastic tube. Nearby, I can see two units (I don't know the english word, but they set the voltage to the motor, which will change its speed), and from one of them a purple cable. This goes into the very same tube as the other purple, and in the same direction, and I guess they meet at the relay, which seems to be inside the car, but I couldn't find it.


This is a very big problem, as I want to be able to use the indoor fan (of course), but as it is now, I have to disconnect the wires to the blower motor to make it stop, and that's not the way it should be.


I'll be very glad for every answer that might help me, as I'm tired of searching through the hole vehicle to find a relay that I don't even now where to find.


What do you mean with "It depends on your Vin # of your engine for a 91 park"? The engine type, like 3800?

What year car do you have? Do you know the VIN #?
Vehicle Identification Number
Electrical location for relays and breaker arrangements are based on type of engine VIN #. Such as a "L" is different than a C type.

On many Buick and GM models the relays for the A/C blower speeds are also in a similar location mentioned before.

- - - - - -

I looked at some of your previous posts and was thinking you are talking about a 1991 Park Avenue.

EDIT... the Purple goes to the BLOWER Control Unit, and then splits to Fuse #2, The Blower control unit is located on the right side of the firewall below under the relay center. Depending on your options, you will have either a Blower control unit or resistors.

Hope this helps.
Edited by: bassasasin

Right, it is from 1991. There are two purple wires, one from one of the resistors, and the other to the blower motor. So those will meet at some point, under the other relays on the firewall?


But the two wires are following the black plastic tube, through the firewall and appears somewhere at the passenger's knees. But then what? I can see allthe wires, butit's impossible to see anythingthat can help me,without having to take the hole vehicle apart. The purple wires are hard to follow, and as I don't know where the relay might be, it's even harder to find it.


It would be a lot easier if the colors on the wires were the same colors as they should be according to the wiring diagram. I bought a repair manual from Hayne's, but there are several brands and models in the book, and that makes it hard to get some information from the pictures. However, I think that the wiring diagrams should be correct, as it describes "Air conditioning system, 1991 and later models". But why does the colors differ? I don't know, and there is nothing to do about it, but I think that all the vehicles of the same year should have the same colors. After all, the models from the different brands are often very much alike.Edited by: andersson

THe purple comes from the blower and then one purple goes to the Blower control unit, somewhere from the blower it splits to places.. F2 and BCU..
According to the schematic wiring diagram I have..
Sorry I can't help more.
Edited by: bassasasin

OK, now I know, my Buick doesn't have a relay for the blower motor. Found out that only vehicles without ACC got one, so I have spend some weeks looking for something that ain't there... Very amusing...


I have ordered a new box containing the resistors for the fan, and a lot of people havehad the same problem, and this box was the thing that needed to be replaced. Hopefully, I have the new part on monday, and I'll try to mount it as soon as possible.


I'll be back for the result...

Now the fan works fine, the problem was the resistor box, or blower control unit, as some call it. I bought the part used, and had to pay $37 for it. With shipping and everything, the bill landed on $52, which is a fair price for a thing as important as this. I got it much cheaper than I should have, 'cause the guy I talked to gave me the wrong price at first. Then he saw what it really costed, $134, but I got him to sell it to me for the price he first gave me. It took four days to get it.


Replacement was easy, and it was done in about 10 minutes.

Great... glad you got it done... was watching for you..

Bass...