Fan power issue

I am having some issues withe my aux fan and after searching the forums I have been unable to locate a solution.

I just recently got 99 XJ, and I noticed that a ground wire attached to my A/C compressor was pulled out of its plug that was attacted to the harness, once I re attached the the wire back into its plug the aux fan would come on for about 1 min then shut itself off, and do this repeatedly. Also, when it turns on it causes a fairly large power drain (the headlights dim and the engine runs poorly.) If you give the engine gas while the fan is on it squeals horribly, but is quiet if you don't do anything.

I disconnected the wire and now that fan kicks on after a min and stays on without the power drain, and no squealing when you give it gas.

Any ideas? Or have I just missed somthing in my looking it over?

Thanks

The squealing is caused when the clutch for the a/c compressor engages to drive the compressor. The load of the engine turning the compressor will slow the engine at idle causing the engine to idle at a labored rate.... The fan belt may need to be adjusted or even replaced...
You donot want to tighten the serpentine belt too much or you could cause damage to the water pump bearing and seal. A KriKit belt adjustment tool can be purchased at NAPA which will allow you to adjust the belt to the proper tension...
The electric fan will operate when the A/C is in use or when the engines coolant temperature reaches approximately 217*.

Thats the odd thing, that fan flicks on and off right after I start the Jeep and its not up to temp, and the squealing is coming from the electric fan not the compressor. The fact that simply disconnecting that one little wire stops the electric fan from squealing baffles me!

Is there a clutch assembly int he electric fan? and the drop in power I see when that ground wire is attached is drastic compared to when the fan kicks on when its not attached.

If this was a Renix I would tell you to start checking the ground cables and straps (there's four total [two on the passenger side with the batt. ground on the block and one on the engine to firewall]).

The only reason I say this is not to waste your time by reading something that does not apply to you, it's because a Renix will do the exact same thing if the grounds are not connected. From experience, if you turn the headlight switch on with this condition, the AC compressor clutch will engauge and disengauge. Most people think the problem is with the AC compressor and disconnect it. I believe the reason why the AC comp usually shows up is because it is self grounded, so everything is looking for a ground through that and ends up energizing the clutch. Plus it is the only item that makes noise when energized.

So check your grounds, maybe that's what it is. Hope this helps.

Also, sounds like the squealing is coming from the alternator. You said there is a large drain when the fan is running. That drain might be so strong, it's dragging the alt. down to full output and when you give it throttle, the belt just can't hold on anymore and starts squealing.

I thought so too, but I took some time to identify the source of the squeal and I am 100% certain that its coming from the fan. Also once the grounding wire is removed from the plug that goes into the harness this problem goes away. I will definitely double check my grounds still though just to be certain.

Anyone know where to find a definitive guide to beefing up the electrical as well?

IronHelix said:

Anyone know where to find a definitive guide to beefing up the electrical as well?

Click to expand...

You could go this route http://www.quadratecforum.com/showthread.php?t=97600

Thanks for the article, that's definitely what I'm looking for!