What did you do to your Cherokee today?
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Originally Posted by dukie564
yea the only way I can think is to cut the PCM wire and run it back into the cab, then back out to the fan. I could splice the out wires together so either pole could give it power, but i could still disconnect both poles from the power source

Yeah it's crappy MS Paint, was too lazy to use Visio.
CF Veteran
Joined: May 2011
Posts: 6,098
Likes: 250
From: DE
Year: 1988
Model: Cherokee
Engine: I6 4.0
Seasoned Member
Joined: Apr 2010
Posts: 407
Likes: 0
From: Baltimore, Md
Year: 1996
Model: Cherokee
Engine: I6
CF Veteran
Joined: Apr 2011
Posts: 14,553
Likes: 1
From: Carrollton, GA
Year: 1994
Model: Cherokee
Engine: Inline 6 4.0L High Output
I'm not a relay expert but isn't there one that could switch between three positions? Or two relays that switch two positions and use a DPDT switch. This popped into my mind and I was drawing it before you edited in that pic. Keeps high current out of the cab.

Yeah it's crappy MS Paint, was too lazy to use Visio.

Yeah it's crappy MS Paint, was too lazy to use Visio.
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
https://www.cherokeeforum.com/f2/ele...82/#post494064
CF Veteran
Joined: Apr 2011
Posts: 14,553
Likes: 1
From: Carrollton, GA
Year: 1994
Model: Cherokee
Engine: Inline 6 4.0L High Output
The ECU works by completing a ground on the control side for the relay that sends the fan power normally. You'd pinch the actual power output from the relay in the PDC to feed the #1 relay in my diagram... guess I should label it PDC. Either way you look at it it's the hot wire that already runs to the fan lol
https://www.cherokeeforum.com/f2/ele...82/#post494064
https://www.cherokeeforum.com/f2/ele...82/#post494064
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
While I was brushing my teeth just now it clicked and I figured out what your diagram is lol. Switching on the control side of the relay..........derp. To be honest I made an assumption of how the system worked then researched after you made your post lmao. Your setup is much cleaner, I like it
Ground to nothing
Ground to ECU
Ground to body/battery
Right?
Ground to nothing
Ground to ECU
Ground to body/battery
Right?
Last edited by salad; Jun 27, 2012 at 10:52 PM.
CF Veteran
Joined: Apr 2011
Posts: 14,553
Likes: 1
From: Carrollton, GA
Year: 1994
Model: Cherokee
Engine: Inline 6 4.0L High Output
While I was brushing my teeth just now it clicked and I figured out what your diagram is lol. Switching on the control side of the relay..........derp. To be honest I made an assumption of how the system worked then researched after you made your post lmao. Your setup is much cleaner, I like it
Ground to nothing
Ground to ECU
Ground to body/battery
Right?
Ground to nothing
Ground to ECU
Ground to body/battery
Right?
CF Veteran
Joined: Apr 2011
Posts: 14,553
Likes: 1
From: Carrollton, GA
Year: 1994
Model: Cherokee
Engine: Inline 6 4.0L High Output







