Codak

2000 XJ

Is there a way where i can wire in a inline switch so that i can turn on the efan whenever i please, but also be able to keep the factory controls? (fan kicks on with a/c and when engine temp reaches 223)

Thanks, Mike

Peter Genneken

deleted

BlueRidgeMark

I strongly recommend AGAINST using any method that taps into a wire going into the PCM. Backfeeding a circuit is very bad practice.

This method eliminates all backfeeding.

moparado

Well i agree with that much!

andrewmp6

You don't need this unless you have a over heating problem then its a bandaid when you have bigger problems.

Tbone289

Here you go. This is the correct way to do it, with no backfeed to the PCM:

https://www.cherokeeforum.com/f51/ri...-e-fan-212243/

EDIT: Sorry, I see BlueRidgeMark already posted that.

moparado

Here's another alternative 'correct' circuit to wire up a efan over ride switch for '97 to 2001 XJs. Can't confirm earlier years without a schematic.

Guaranteed no 'back feeding' to any PCM output pin.
Been using it going on 2 years with my incorporated 5 min. engine off efan delay to deal with my heat soak issue. Works great and i use it a lot.

Take your pick, BlueRidgeMark's and my circuit will both do what they're supposed to do.

Whatever you decide to do, make sure the added aux relay power pin 30 fuse is located as close as possible to the (+) battery terminal.

Codak

Thanks everyone for the replies. The only reason i want to do this is because i am having a heat soak issue, even tho i have wrapped both injectors and fuel rail with heat resistance tape. And i have the factory recall heat shield but am still having the issue when i am idling for long periods of time in this hot south florida traffic. Hopefully this will help.

moparado

Does your efan turn on at all? AC on?
If your efan does not turn on during hot idle, there could be something going on with the cooling system that needs attention first before adding an efan over ride switch.

I also installed all the TSBs for heat soak which seemed to help some but did not cure the problem.

The issue i have/had is the efan turned on way too late at stand still hot idle eventually causing a rough running engine which is probably an early stage of vapor lock.
Can't be good for the 331 head.

My 2k has also had a history of brief engine OFF/engine ON heat soak vapor lock the reason i added the 5 minute engine off efan delay.
I turn on the efan delay every time i shut down the engine which cured that heat soak problem for good.

Codak

Everything is working as it should. I just have the same issue as you. Efan truning on way to late. I'm hoping this will solve my problem.

andrewmp6

Get your exhaust manifold/header ceramic coated inside and out,And make the intake manifold if needed.

andrewmp6

or even try some water weter it does drop your temp about 20 degrees