Power/ Comfort Mode for Transmission
03-21-2019 | 05:47 PM
#1
Thread Starter
Newbie
Joined: Mar 2019
Posts: 18
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Model: Cherokee (XJ)
Power/ Comfort Mode for Transmission
First off I have a 1988 Jeep XJ 4.0 Automatic. I’m having issues with my power mode not engaging with the switch. I took apart my dash to take the switch out and tried doing the bypass I’ve seen posted on here and still nothing. It use to work just fine about 2 months ago or possibly less. I’ve checked the fuse and it is good. Anyone have any ideas of why it’s not switching to powe mode? Is there a relay I might have to change?
Im just tired of my Jeep being gutless now that it doesn’t work. Any help will be appreciated.
Thanks in advance!
Im just tired of my Jeep being gutless now that it doesn’t work. Any help will be appreciated.
Thanks in advance!
03-21-2019 | 11:11 PM
#2
CF Veteran
Joined: Dec 2017
Posts: 4,073
Likes: 1,128
Year: 1989
Model: Comanche (MJ)
Engine: 4.0
Do you have power on the black-yellow wire going to the switch? The switch tells the trans computer to select power mode by pulling the tan wire up to 12-volts. Does the bulb in the switch light up? The bulb is connected between the tan wire (to the trans computer) and the black ground wire.
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03-27-2019 | 10:30 PM
#11
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,565
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Sure. Meter set on DC volts. 20 volt scale. Black lead to good ground. Red lead to the tan with tracer. Be sure key is on. Do the same with the one with a tracer on it. Leave the black one alone at this point.
03-27-2019 | 11:03 PM
#12
CF Veteran
Joined: Dec 2017
Posts: 4,073
Likes: 1,128
Year: 1989
Model: Comanche (MJ)
Engine: 4.0
If the light on the switch goes on/off when you switch it, then the fuse should be good and the switch is probably wired correctly. With the volt meter, verify that the voltage of the tan wire changes between zero and battery voltage when switched. Both at the switch and at the trans computer connector. The trans computer is under the passenger side of the dash, bolted to the back of the panel in front of the passengers knees. While under there, check the fuse and resistor that are wrapped up in the wiring harness near the computer too.
03-27-2019 | 11:36 PM
#13
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,565
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
If the light on the switch goes on/off when you switch it, then the fuse should be good and the switch is probably wired correctly. With the volt meter, verify that the voltage of the tan wire changes between zero and battery voltage when switched. Both at the switch and at the trans computer connector. The trans computer is under the passenger side of the dash, bolted to the back of the panel in front of the passengers knees. While under there, check the fuse and resistor that are wrapped up in the wiring harness near the computer too.
04-27-2019 | 04:00 PM
#14
Thread Starter
Newbie
Joined: Mar 2019
Posts: 18
Likes: 0
Model: Cherokee (XJ)
Ok I’ve tried looking for this fuse under the dash near the transmission computer but I cannot find it. How close was it to the computer?. The only thing I have close to it is a blue and yellow wire coming into one connector before the main plug. It looked like it was done ghetto. Had duct tape holding the wires together and a weird connector allowing both wires to come into one. I’ll take a pic and show you what I’m talking about once I’m done fixing the connectors with proper connectors not duct tape.
