Hello all....I would like to first say thank you to all of the contributors on this forum. I acquired a 1987 Jeep Cherokee Laredo 4wd a few months ago and have been working on making it my own. I have learned a heck of a lot from this forum. I unfortunately have run into an issue that I am not able to solve no matter how much I search this forum and others so I have officially joined and am reaching out for help.

I installed an AW4 override switch from Montana Fab a few days ago. I noticed prior to installing that the instructions stated it was for 1988-2001 Cherokees. I reached out to the company and was informed that if I have an AW4 transmission it will work despite my rig being a 1987. Their instructions were very detailed and I made sure I followed them, double and triple checking my work.

The issue I have after installation is if I have the switch turned to "1" and the shifter in 1-2, the transmission feels like it is in second or maybe third while taking off. Same thing if switch is set to "1" and the shifter is in 3. When switch is set to "1" and shifter is in D the transmission feels like it is in 4th and will barely take off. I get the same results in 1-2, 3 and D when the switch is on "2". If I have the switch on "D" the transmission shifts fine through the gears while the shifter is on D, however, if I have the shifter on 1-2 it will not shift out of 1st (exactly why I wanted the override switch).

Again, I have checked my wiring and it appears to be installed per the instructions. The TCU connector diagram in the instructions matched my connector in relation to wire colors and locations with the exception of the power ground, pin D7. The instructions listed it as black and tan. Mine was just black but was located in the D7 location. The other wires per the instructions are:

C15-purple/white-S2 solenoid
C16-dark blue/white-S1 solenoid
D16-yellow-ignition run/on

The wires on my connector matched those listed above.

The only other transmission "mod" I have done is the power switch override using a jumper wire per Cruiser's website. I have also refreshed all grounds.

While my transmission now holds 1st gear like I wanted it to, I would like to get the $200 switch to work. I highly doubt I will be able to return it after installing it.

Can anybody provide any insight on my issue? Is my 1987 connector different from the 1988 connector?

Any and all help is greatly appreciated.

Thank you.

 

Just throwing it out there, but best practice means a diode should be in the circuit to prevent any possible feedback

If there is no diode, check archives to show how they fit

May not be your issue

 

Thank you for the reply AWG. I will look into this.

 

Just wanted to provide an update. Hopefully this will help someone in the future.

I reached out to Montana Fab and they were very helpful. Some of the older cherokees have different wiring for the tcu. The wiring is as follows:

White wire on the override needs to go to the purple/white from the computer, Blue wire from the override need to go to the purple/white from the vehicle side
Brown wire on the override need to go to the blue/white from the computer, Green wire from the override needs to go to the blue/white from the vehicle side.

Everything works as it should now.

-JC