Electric Fan Help!

[RedHeartbeat]

The low speed trigger wire on pin 42 needs to run to pin 42 and the green line on the green a/c connector that way the fans run on slow at operating temp or when the a/c is on. The high speed relay would be triggered by pin 33 only and you would get high speed fans only when above the trigger value programmed in the PCM. You could also jumper another lead on the high speed relay to run into the cab so that you can manually turn the fans on in stop and go traffic.

You may have to wire a diode into the individual ground circuits to prevent false feedbacks from other grounds but that's simple enough. A diode is a one-way check valve in the electronics world, allows signal to travel 1 direction only.

[bulldog5.3]

wow, i have no clue what you guys are talking about?
I replaced the 8 gauge wire on the alternator with a 0-2 gauge wire and i saw a little difference, but didn't fix the problem.
My fans come on when i turn my heat on and a/c on? this is a mess i regret even buying the radiator, fans, and harness, (just angry that when you follow directions like your suppose to and it still won't work!!&#33
I think allen should help us, but i have been playing phone tag with him for 2 months now.

[COWL327]

Originally posted by bulldog5.3@Nov 11 2005, 01:47 PM
wow, i have no clue what you guys are talking about?
I replaced the 8 gauge wire on the alternator with a 0-2 gauge wire and i saw a little difference, but didn't fix the problem.
My fans come on when i turn my heat on and a/c on? this is a mess i regret even buying the radiator, fans, and harness, (just angry that when you follow directions like your suppose to and it still won't work!!&#33
I think allen should help us, but i have been playing phone tag with him for 2 months now.

Keep trying i talk to him all the time

[RedHeartbeat]

If you're going to be at the dyno shop tomorrow I'll look over what you have.

[bulldog5.3]

Do you think this is something that allen should warranty or fix, I paid like $100.00 or more for the harness and if it needs to be modified i think he should do it, what do you think? By the way thanks for the diagram i wil compare it to mine.

[RedHeartbeat]

Depending upon how you have it wired may be all the difference. Your pos and neg supplies to the fans should be on the battery or as close to it as possible. The additional load the fans put on the power lead from the battery is most likely what is causing your surges. The main wire coming from the battery to the fuse block was not designed to handle the load of the fan motors. I think he has the right wiring process. We'll see tomorrow.

[bulldog5.3]

so did you get yours working right yet?

[RedHeartbeat]

This wiring harness diagram is assuming that pin 42 ground triggers at low temp on and when pin 33 ground triggers, pin 42 is still grounded at high temp turn-on. This circuit will turn the fans on low when the a/c is turned, even at startup, using the second relay to trigger the ground for the first.

Fans will be off until low temp trigger 42 grounds in the pcm unless the A/C is turned on. If A/C is on, then fans are on low. The only time you will get high speed fans is if you have a hot radiator over 210 or whatever the PCM is set at and the PCM is setup to trigger high fans.

The A/C green labeled connection would best be connected to a wire that is energized when the A/C is turned on in the cab, not one that cycles with the compressor.

Yes, I have already built and bench tested this.

I must admit, this is pretty close to the diagram AKLIM posted with some changes.

Hollar if you have any questions.

[COWL327]

Use2bo said thank you thank you thank you thank you! Your are the man! His internet is down and I could do the honors. Thanks for coming today and it was great talking to you. Lets do it again pretty soon

[RedHeartbeat]

We'll do that.

I added a couple extra notes and corrected pin 33 and 42 locations.