Power/comfort transmission issues

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Mar 14, 2012 | 02:54 AM

PNWjeeper

Thread Starter

CF Veteran

Joined: Feb 2012

Posts: 1,206

Likes: 2

From: Southern Oregon

Year: 1990

Model: Cherokee

Engine: 4.0

Power/comfort transmission issues

So here is my problem I have a 90 xj 4.0 with a power/comfort transmission switch and every time I turn on the power switch when towing and give it enough gas to shift the fuse blows. I think it's a 7.5 amp, the first time I happened I replaced it with a 10 amp and that blew and the last time it happened the only fuse I had available was a 15 and THAT still blew. So my question is what might be causing this.

Mar 15, 2012 | 06:55 PM

PNWjeeper

Thread Starter

CF Veteran

Joined: Feb 2012

Posts: 1,206

Likes: 2

From: Southern Oregon

Year: 1990

Model: Cherokee

Engine: 4.0

Really nothing

Mar 15, 2012 | 07:16 PM

salad

Herp Derp Jerp

Joined: Nov 2011

Posts: 18,251

Likes: 17

From: Parham, ON

Year: 1999

Model: Cherokee

Engine: 4.0L OBD-II

Fuses blowing is caused by a circuit shorting to ground. I'd start by disassembling the switch

Mar 15, 2012 | 07:34 PM

cruiser54

::CF Moderator::

Joined: Aug 2011

Posts: 43,971

Likes: 1,579

From: Prescott, Az

Year: 1990

Model: Cherokee (XJ)

Engine: 4.0

The switches tended to short out internally, something to do with the light inside IIRC.

The switch can be eliminated and the TCU left in the power mode quite easily.