[justanotherjpr]

Originally Posted by squirlgod

my question is this...for people that use a separate relay and just power the fan the old fashion way, isn't it bad to attach hot 12v to the current relay-triggered 12v at the fan? thus you are sending 12v the wrong way to the relay in the PDC? Im thinking this is especially bad when the relay engages due to A/C or otherwise and its fighting the 12v you are already providing up that wire.....hopefully that wasnt too confusing

That's not a concern with this setup

[squirlgod]

Yeah I thought about it more today and I realized that it should not harm any relays or circuits....I think I will just go with this set up and not mess with any CEL

[dagr8tim]

IIRC, I thought the fan has the switch on the negative side. So why not tap the ground and run a 2nd ground through a switch? With the switch off, the fan will act normal. With the switch on, the fan will always be on.

[smccollamjr]

On my '96 the 12v was switched.

[donthelegend]

Its the 12V thats switched on my 99 as well.

[joe108]

New to Cherokees, so has anyone come up with a write up that works on the newer (2000) Cherokees without the CEL coming on or frying the computer? So far in reading this post, "I" would be the one that frys the computer and burns my Cherokee to the ground.
I'm not good at electrics and a good write up with photos would help, or a recommended link to another site, thanks

[RedRyderXJ]

Just checking here but all you do is attach the dark blue pink stripe to ground via the switch?

[joe108]

From my reading, that back feeds a ground to the computer and triggers a CEL.

[justanotherjpr]

Originally Posted by joe108

New to Cherokees, so has anyone come up with a write up that works on the newer (2000) Cherokees without the CEL coming on or frying the computer? So far in reading this post, "I" would be the one that frys the computer and burns my Cherokee to the ground.
I'm not good at electrics and a good write up with photos would help, or a recommended link to another site, thanks

I just wired a new relay with a switch and power to the hot side of the fan. Either the computer turns it on or I do. No CEL and been this way for 3 years with no problems.

[JustinGB]

Just did this on my 95. Want to give a big thanks to the OP! Works like a charm

[mtbikemarc]

Hey guys! Awesome thread...can't wait for this to work for me.

So, my aux fan hasn't been working on it's own, so I've been jumping it at the relay for the past few months. I got sick of it, hunted down this thread and tried it out. No luck.

I actually cut the Blue/Pink wire at the PCM. Wired the switch in correctly (even used only a jumper to ground) and the fan won't turn on. However, I can hear and feel the correct relay clicking back and forth. I've used multiple switches and relays but it the fan won't work unless I jump 30-87 using wire.

I called my electrical buddy and he has no clue either. Gonna look at it in a few days but that involves a drive. Hope someone here can help me!

Yes, I'm sure it's the right wire because I can feel the AUX FAN relay clicking on and off as I pull the jumper (blue/pink wire to battery ground) on and off the battery.

[donthelegend]

Have you tried replacing the relay?

[mtbikemarc]

Yup. As stated previously, i tried multiple relays and multiple switches :-). I just don't get it. Tried it w Jeep off, on and running. Still wont work.

[go-big]

Unplug the fan switch In intake

[mtbikemarc]

Fan switch intake? U mean the coolant temp sensor? Im not sure what that is.