gamma-wes

Alright gang. I have had some issues, to say the least, with my car since I bought it. The wiring was in poor condition and many wires in the harness had been cut and crimped or poorly soldered. The clip on the harness that plugs into the fan wouldn't stay connected and that caused some near-over heating issues.

I have since gone through the tedious process of putting a new harness in my car. That allowed me to solder the MAP sensor pig tails (stage 1 upgrade already in place) instead of their original crimp connections the last owner made.

The idle is nice and smooth. No random hiccups like before. The fan clipped right into the harness instead of giving me grief like before. It even cleanly hits 23 psi now with no creep. The only problem now is that the fan won't come on at all anymore. I don't know if it got fried from all of this on/off action that was going on before or what, but it simply will not come on.

Does anyone know what wires do what on the fan? I need to know what voltage, resistance, current, etc. are supposed to be put out of the control module and into the fan so I can test the two.

I'm not a "take it to the dealer" type guy anymore and mechanics in my area will either cost a fortune or not be worth their salt. I'm a son of a master diesel mechanic and spent around 12 summers with my dad at his shop learning from him. We built hotrod projects over the years and worked on anything the friends and family would bring us. I'm definitely not an idiot when it comes to getting under the hood.

Before the peanut gallery chimes in on smart comments about not getting enough information or needing to see what I'm looking at, just know that I only need information on what the output and input is. The area is highlighted above. I have done some searching on the forums to yield no conclusive results.

whopper

Peanut gallery? I did have a question but its probably too obvious and out of scope, so I guess I am out of this one.

firemangeorge

Check back later. I'll take a look in the repair manual and see if I can find any info that might help.

gamma-wes

You're only the peanut gallery if your advice or question comes with a subtle insult.

Thanks.

I'm reading a full 13.67 volts across what I'm assuming is the hot and ground. Haven't checked the other side of the module yet.

donbrew

Oh!

whopper

Well I had what I consider to be a good and helpful question - but obviously you don't want any questions - just answers. So I won't ask it. Have fun.

firemangeorge

Unfortunately, the repair manual wasn't much help. There was no listing of voltage checks or such at the module.

The diagnostic and repair procedures in the manual were done with the Tech II scanner. Most of what it showed was checking the power supply to the fan assembly. If relays and such were found good and supplying power to the module, what I read was the next and last step was to replace the fan assembly.

Seem to remember a recent post about someone being able to find just a replacement module without buying the whole assembly.

gamma-wes

Just tested the module. I was getting between .08 and .20 volts, constantly fluctuating. That's obviously the issue being that my car was over 200 degrees and my ac was on. The voltage should have been way high at that time. I was assuming at least 12 volts would come through.

Does failing module make sense here? That's the way I'm seeing it. I can get the module alone from gmpartsdirect.com. Doing that ASAP.

Lucky

I have never seen any diagnostic pin outs for the cooling fan module and I would guess its because the module is commanded by the PCM in dataplexing voltages. (Computer talk)

I think your on the right track.

My understanding of the cooling fan is The module is the common failure.


You use to have to buy the module and fan motor as a complete assembly. I would guess that an old fan motor that is pulling too amps could burn out the module. ( just a thought ).

SS fan

I don't even know how to grow peanuts...but when my SS would not cool I had the cooling fan replaced. Been cool ever since, so to speak. I paid 200.00 to get the job done................