Relocating the ECU on a 2.6 TrooperDate: 2002, Sep 29
Author: Tad Grosvenor
The ECU (Engine Control Unit - the computer that runs the engine) is located at possibly the lowest point on 2.6l Troopers. It is under the console between the front seats, bolted right to the floor. It is relatively protected there, but it is also about the lowest point in the truck. If you do any water crossing, you may find that it will get wet. I don't do many water crossings, but I have been known to ford creeks that are above the level of the floor.
The ECU under the console:
I looked around at the options (sealing the ECU, cutting the wires and extending, etc) and decided that if I took up the carpet and un-routed the ECU cable, it would reach to behind the glove box. Unfortunately upon removing the ECU, I found that there wasn't enough room behind or beside the glove box, but if you don't have cruise control the ECU may fit to the right of the glove box. I decided to mount the ECU on the floor of the glove box. After removing all of the junk that had collected in the glove box, the only thing that wouldn't fit after putting the ECU in for a test fit was my pair of winter gloves. Those can now ride in the center console.
The ECU sitting in the glove box:
The hardest part of this whole procedure was routing the wiring harness for the ECU. It has about 2 dozen wires in it and isn't terribly flexible. Getting it out from under the carpet wasn't hard, but you have to remove the bolt under the gas pedal to be able to lift up that part of the carpet. It is 12mm and be prepared to spend some time with a box wrench taking it out. (Hint: here is a good excuse to get that set of ratcheting box wrenches that you have been wanting). Before removing the carpet, take the 4 screws out of the center console (near the floor, 2 on each side) and lift it out of the way. If you have an automatic, remove the trim that is around the shifter as well (3 screws). Also remove the threshold (5 screws) and set it aside for the final attachment point for the carpet.
The now empty area under the console, with my wires in it:
The wire can then be pulled out from under the carpet and the padding and placed under the radio. There are a few metal clips that are bent over the harness, holding it down, but they are easy to deal with by just using your fingers. Now is the time to put the carpet back down. You can also put the console back in.
The bolt behind the gas pedal:
There is an open area above the radio, just a but underneath the heater controls that is just about the right size for the harness. I fed the harness up to the left of the heater, and over the vent "hose" and then across under the heater controls. From there it is easy to pass it over a metal dash support into the space behind the glove box. Be careful to protect the harness from chafing against anything metal.
ECU harness above the radio:
I chose to cut a hole in the back of the glove box, at the bottom. It is about 1" by 2". The harness fills about half of it, but the connectors need a siginficantly larger hole, and I'm not too worried about things falling out. You could easily seal this hole if you'd like.
The ECU isn't bolted down, but it is a force fit to put it in behind the screws that hold the glove box in. It just popped into place and had no movement at all. You may have to play with the harness to get it to fit behind the glove box when it is back in place. I removed some of the electrical tape holding the ECU diagnostic wires, and moved them closer to the front of the glove box where I taped them back together again.
That is about it. Put the stuff back into the glove box on top of the ECU. I plan on making some kind of cover for it, but I don't carry screws or anything else that might come in contact with the connectors on the ECU, so it isn't a top priority of mine right now.
The ECU in its final position, with my junk back on top of it: