Park Ave fan runs constantly No Climate control

[madmark67]

Haven't seen this one yet so I'm hoping someone can help me out. I have a 1992 Park Ave base model WITHOUT climate control. It is the straight Heat / A/C controls with a multi speed fan. Woke up to drained battery. When re-charged I found my Heating fan running constantly. (Have had many probs with controls) Searched forums & all I can find is the solution with climate control. I removed the heater controls from the vehicle to try to match up at salvage yards, but the fan continues to run with controls out & key off. When I hook up the battery I also hear a lot of the relays clicking under the hood, although I don't know which ones. Any suggestions?

[gmtech1]

Have you tried changing the blower relays? This may have more than one blower relay. Sounds like maybe one is shorted.

[imidazol97]

Originally Posted by madmark67

Haven't seen this one yet so I'm hoping someone can help me out. I have a 1992 Park Ave base model WITHOUT climate control. It is the straight Heat / A/C controls with a multi speed fan. Woke up to drained battery. When re-charged I found my Heating fan running constantly. (Have had many probs with controls) Searched forums & all I can find is the solution with climate control. I removed the heater controls from the vehicle to try to match up at salvage yards, but the fan continues to run with controls out & key off. When I hook up the battery I also hear a lot of the relays clicking under the hood, although I don't know which ones. Any suggestions?

Your high speed blower relay may be burned and stuck to the contact. Looking at the FSM that's the only option I see. Do any of the three lower speeds work? Is the fan running at high speed?

The relay might unstick if you tap on its cover with something that gives a good vibration. The high speed blower relay is a single pole double throw. The blower motor relay, a different relay, is a single pole single throw on that car.

The relays are in the Relay Center cover on the firewall. Individual relays have a flat spring metal piece underneath that snaps over a catch to keep them from sliding forward afteer they are pushed back into the holder. Use a steak knife under the relay to lift up on the flat snap spring piece to pull them forward and out.

According to the 93 Park Avenue factory service manual, from the left, passenger side, facing the relay center: AC compressor, horn, high speed blower, blower motor relay,

http://i86.photobucket.com/albums/k1...lay502chj8.jpg

[madmark67]

So far I've re-soldered 6 points on the circuit board & had to jumper the ground connection because the joint was so bad. But it works, sort of... So now I have to smack the control panel to get the light so I have control over the mode. Then I have to squeeze the control by the fan switch to get the fan to work intermittently. It runs constantly on the lowest fan speed, so I will start there troubleshooting the relays. Thanks for the pic, it was very helpful. I also see something mounted on the fan shroud where the module would be on a climate control model. Looks 'lectrical...

[imidazol97]

Originally Posted by madmark67

to smack the control panel to get the light so I have control over the mode.

What light is that? Is it the readout for the digital numbers display for the temperature?

[madmark67]

No, to get the lights on the buttons to come on. Each button has an indicator light on it, to indicate mode. I did some more sleuthing. I pulled the device from the fan shroud, & it is a trio of old-school wound resistors, presumably for fan speed control since the fan switch is just a selector switch.
It appears that I am getting a constant 12v signal on the N.C. contact (blue wire from resistors, presumably the common ) to the HS Blower relay sending 12v thru to the Purple wire to the fan motor. I havent gotten beyond that to find which wire is sending the signal TO the resistors.
Since I have the fan controls out of the dashboard & disconnected, is there another module or set of relays in between the fan switch & the resistors? If not I cant imagine where the voltage is coming from unless I have burnt & fused wires under the dash.