Where to mount ECM in later model Grand Wagoneer

[Mr. Goatman]

Where is a good place to mount the ECM in an 87 GW? Where did you run the cables through the firewall?

[FSJ Guy]

You can use an OEM hole on the driver's side. It's oval shaped and the plate is held in with two screws accessible from the inside. There may be carpet insulation over the hole, but it is pre-cut. You will have to plug the hole well, however. Otherwise water will splash up and wet your legs. AMHIK. You can stuff the ECM up under the dash above the steering wheel if you don't need regular access to it for tuning.

Or you could cut a hole on the passenger side and route the bundle in there. Watch out for the exhaust, however. It's easy to bolt the ECM to the air conditioner unit inside, too. Just don't use LONG screws!!!

[jaber]

This pic is just under the heater/fan box. 2" hole saw...











HTH...

[Mr. Goatman]

I got down under the dash to mark and drill a hole under the heater box. About 6 inches left of your hole I found a perforation in the insulation. When I removed it there is an access plate screwed on that when removed leaves about an 1.5 x 3 inch hole. I ran the harness through and played with the routing of wiring around the engine to the approximate location it will go. Everything looks like it will fit fine. Thanks

[FSJ Guy]

I got down under the dash to mark and drill a hole under the heater box. About 6 inches left of your hole I found a perforation in the insulation. When I removed it there is an access plate screwed on that when removed leaves about an 1.5 x 3 inch hole. I ran the harness through and played with the routing of wiring around the engine to the approximate location it will go. Everything looks like it will fit fine. Thanks

Make sure your wiring is well away from the exhaust manifold. IIRC, that hole is really close to the exhaust pipe.