cooling fan

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Jun 27, 2017 | 09:57 PM

MaxximuS

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Joined: Apr 2015

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cooling fan

So i have a cooling fan issue. first off i have replaced the connector with mouser electronics 50a connectors, i replaced the pwm but that doesnt seem to be the problem. Also i checked the fuse , number 25 in the engine bay and its fine. The fans are not running when the engine seems to get up to temp.
Today i started it with a/c and the fan was on. I drove it 10 mins and stopped , left it running, no fans temp was 217 and climbing.

When the car was first started i measured the voltage coming from the pwm and it was 9. something volts.

any ideas?

Jun 28, 2017 | 08:13 AM

BlindSpot

Le Mans Master

Joined: May 2016

Posts: 7,283

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From: Florida

Only thing left is the fan control module. They do fail. This is a transistorized circuit that converts the PWM pulses, much like a large relay, to high amp fan variable voltage. When they fail, they'll act like you're describing. Fan starts out running then as run time ensues, the circuit heats up, fails to relay. Also, don't make much of voltage at the PWM. When running this should be a variably pulsed signal commensurate with the fan run % the ECM is commanding.

BTW - If you decide you need to go that route SHOP prices. I found a $60 something swing on high to low pricing on the same AC Delco/GM module P/N. Check price and ship combined. One of the GM houses makes up the low price difference in shipping costs. I paid $122 shipped for the module a few months ago.

Last edited by BlindSpot; Jun 28, 2017 at 11:03 AM.

Jun 28, 2017 | 11:09 AM

MaxximuS

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Joined: Apr 2015

Posts: 207

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thanks for the helpful reply. I replaced this, acdelco 15-80803. which i thought was the pwm and the fan control module. i thought this was powered from the ecm. but still my problem is as described above

Jun 28, 2017 | 11:19 AM

BlindSpot

Le Mans Master

Joined: May 2016

Posts: 7,283

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From: Florida

Quote:

Originally Posted by MaxximuS

Might just be a difference in nomenclature. The GM control module p/n is 10377609. I PMed you as well. I assumed you were just referring to the PW signal wire in the harness.Yes, 1580803 is the fan control module. There is not much left to fail here unless the ECM has failed. I'd like to see a log on the fan while the car is running at different temps. You can do it with a tech II and other dataloggers. I use dashlogic to read mine on the fly.

If you want to test the actual fan itself, there is an easy way from the connector. Unplug it. Make two short 10 or 8 ga jumper wires with blade terminals on each end. From the connector - loop the two blacks with one jumper, loop the two reds with the other. This connector is hot at ALL TIMES, so the fans will run with no key on. Be prepared for a good spark as well. If the fan runs, then it's good.

Last edited by BlindSpot; Jun 28, 2017 at 11:36 AM.

Jun 28, 2017 | 01:39 PM

schpenxel

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Joined: May 2004

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From: Raleigh, NC

St. Jude Donor '15

I'd want to log it and see what fan % is being commanded first, just to make sure the computer is trying to run the fans when AC is off. Obviously it should, but perhaps something else is going on with that side.