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Cooling Fans Question


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I See... -_- so is that normal for cars to do that? (when im at a long light or idle my car for a little my gauge goes a lil past the half mark, but never seen it go much futher...)

In general, yes, it's normal...especially if you're not using A/C.

Cooling fans are controlled by two main inputs: the A/C and the coolant temperature. Without A/C use, the cooling fans are controlled entirely by coolant temperature. They will remain off until the coolant reaches a temperature of about 229*F. Your temperature gauge will start to come off the "straight-up" mark at about 220-222*F in my experience (from my '97 SLS). So pretty soon after you see the gauge start to move a little, you should hear the cooling fans engage (on LOW speed), and the gauge will soon thereafter return to "straight-up". The cooling fans turn back off at around 212-215*F as I recall. If the engine coolant temperature gets up to about 235*F, the fans change from LOW speed to HIGH speed. They return to low speed in the 220*F range I believe.

Now, all that is without A/C. If the A/C is on, regardless of engine temperature, the cooling fans will cycle on and off. This is because there is an immediate thermal load on the A/C condenser, and it needs airflow across it to exchange heat with the air. So the fans will cycle on and off if your A/C is on. 90% of the time, this is enough (the fan cycling, on LOW) to maintain coolant temperature in the 200-220*F range. I've never seen the temperature gauge on my '01 STS come off "straight-up", ever. But I also don't use it under real extreme circumstances, either. I don't sit in traffic for hours on 100*F days with it. Under those extreme circumstances, the fan cycling may not be enough to maintain coolant temperatures, and the gauge might start to creep up. When it gets to around 229*F, the fans will change from a cycling to a constant on (again, in LOW speed). And like before, without A/C use, if the temperature does creep up further to 235*F, the fans will change from LOW to HIGH.

thanks...

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Dana F, i now see that you are a supporter, as you said, that you were going to do ...

i like a man of his word !!! good deal sir ...

Lane

THANKS... just showing my appreciation of all the support i have recieved, and hopefully can be of some help down the line to someone..!

That's great Dana glad you are a supporter now..

no problem... thanks for your help... im sure i have many more question to come LOL

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  • 3 years later...

Ok I just looked at the cooling fan schematic, the PCM grounds circuit 335 (dk green), that energizes both cooling fan motors. BUT. Power is supplied to the motors through the cooling fan 1 relay, contact circuits (your #1 relay is good as one fan runs). Relay 1 energizes circuits BLK (532), White (504) and Lt Blue (409), and <b>COOLING FAN #2 RELAY</b> contacts. The fans are connected in series circuit, thereby sharing the 12 volts equally causing them to run SLOW or LOW SPEED.

As a result of this, I would check cooling fan relay #2. If the contacts are bad, the second fan or the RH fan energized through Lt Blue (409) won't run.

Check the #2 relay, it will be the relay with WHITE, ORANGE, LT BLUE and DK BLUE wires going into it. My guess is that the LOW SPEED contacts are burned, if you tap it with a broom stick while the AC is on, I would not be surprised if the fan started. You could take the relay apart and inspect and clean the contacts or replace it..

Mike

Can you describe to me where the relays are located on my 98 Eldorado ETC?

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Can you describe to me where the relays are located on my 98 Eldorado ETC?

:welcomesmiley:

Cooling Fan Relays.doc

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Than you very much!!! Is one of them the "output driver module 3"?

Can you help me locate the camshaft position sensor too?

quote name='WarrenJ' date='12 November 2011 - 09:35 PM' timestamp='1321155343' post='198601']

Can you describe to me where the relays are located on my 98 Eldorado ETC?

:welcomesmiley:

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. . . Is one of them the "output driver module 3"?

Ya got me with that one. Never heard of it.

Can you help me locate the camshaft position sensor too?

See attached (Item #1).

EDIT: Oops. Shoulda made the drawing a little smaller.

post-416-132122567544_thumb.gif

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There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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Some codes that are not fully updated to manufacturer-specific text just refer to driver outputs of the modules. They are usually relay grounds but may be PWM signals to another module. They control something, or send data to another module to have it control something. What you need is a better code list. We may have it; what is the OBD DTC?

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