: Cooling Fans



mndeville
01-13-09, 10:57 AM
Just wanting to run something by you guys… my 97 Deville Vin Y has had a P1660 from the time I bought it. I have the dealer service manual here and used it as a guide. I chased everything from relays to bad grounds to shorted out wires. I finally went as far as to re-wire completely new relays per the diagram as the old wires had been hacked into, at one time, to make the fans come on with the key; this was revered by the time I bought the car, but the evidence was still there.

Long story short, I did everything by the book, then rewired it all per the book, ran the wires to the PCM right up to the harness, connected, soldiered and heat shrink the connections and still…. No fans…. Still the code… no matter where the engine temp was, ac on or off, etc. I checked the temp sensor with the yellow and black wire, all was where it should be. Grounded the relays to see if the fan would kick in per the book, nothing; so I but the bullet and replaced the PCM, had it flashed, etc. and still there are no fans.

So in went the aftermarket fan control. I have it set start the fans at 225, stop them at 210… is this appropriate range? The AC compressor kicking in will fire them on low, as it heats up it will put them on high, and it seems to have good control over the temp but I want to make sure my setting is optimal. I used a thermal temp. sensor to program when the fans start and stop. That’s what I wanted to run by you.

Also; will the pcm throwing that code affect the computers control or reading of anything else and adversely affect anything like mileage?

Ranger
01-13-09, 12:24 PM
So in went the aftermarket fan control. I have it set start the fans at 225, stop them at 210… is this appropriate range?
FSM should tell you, but that sounds right.


Also; will the pcm throwing that code affect the computers control or reading of anything else and adversely affect anything like mileage?
I don't think it will affect anything else.

Eric
01-14-09, 06:42 AM
Temp specs for my 2000 SLS are:

The PCM commands low speed fans operation under the following conditions:

Engine coolant temperature exceeds approximately 106°C (229°F). The fans will switch from low to off when the coolant drops below 102°C (216°F).
A/C operation is requested.
After the vehicle is shut off if the coolant temperature at key-off is more than 151°C (304°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes.
The PCM commands high speed operation under the following conditions:

The engine coolant temperature reaches 112°C (234°F).
A/C refrigerant pressure exceeds 240 psi. The fans will will return to low speed operation if the refrigerant pressure drops below 190 psi.
When certain DTCs set.
If the cooling fans operate when commanded off and no DTCs are set, either a cooling fan relay is stuck on or a cooling fan circuit is shorted to power.

mndeville
01-19-09, 02:56 AM
thanks a million guys!