EEC Relay Location

[Joe321]

Hi, how's it going? I bought a 86 bronco II about 5-6 months ago, drove it for 2 days, then it just quit running on me, I've been threw all the electronics and I literally ripped the dash off, looking for that little EEC relay and fuseable link! I can't find it anywheres! Does anyone have any pictures or anything like this that can help me? And I recently found out my truck was purchased in mexico city, so I don't know if this would make the location of the relay change or what? But it's driving me nuts! Any help would be appreciated, this is my first time on ranger station and I hope I get more response then on other ford forums.

 

[unoleisu]

According to my 87 Bronco II 2.9L electrical manual, the EEC power relay is on the right hand cowl side. ( under the dash, passenger side, mounted by the passenger door, behind the plastic kick panel) It's a small relay just above the Electronic Control Assembly computer. (a largish flat metal box) It has a red/light green wire, black/light green wire, Dark brown wire, and two yellow wires going to it. Didn't see a fusable link in the schematics except on the yellow wire. It is fusable link "L", this is at the starter relay. I have no idea if It being purchased in Mexico makes a differance.

 

[adsm08]

Uno is right. The PCM power relay is behind your air box. You have to pull that little plastic pin out and remove the cover. If they are both factory relays then the fuel pump will be green, and the PCM will be black.

Be careful testing on those lines. It is really easy to fry the computer if you aren't careful.

 

[Joe321]

Thanks guys, I'll go check it out, and the pcm fried before because the guy I had originally bought the truck from had a wire going directly from the battery to a switch, and the switch was connected to the test port for the high pressure fuel pump, I hate when people don't fix things correctly!

 

[unoleisu]

Yeah, I purchased a 92 Explorer recently to use as a doner for M50D and 4.0L, and was amazed at the length the previouse owner went too, to not fix electrical issues right. There was literally speaker wires used to bypass the harness, and even some weird switch that had to be on to allow the engine to start. Wires cut and hanging everywhere, and stuff tied on with electrical cords. I can't believe he drove it the way it was rigged. Alot of mechanical rigging as well.
Educating yourself on your vehicle is worth far more than you'll ever think.

 

[Joe321]

Yeah, that kinda rigging is what I refer as redneck engineering, ya know, something ya do while on the trail to get yourself home and fix it right later.

 

[unoleisu]

Hmmm......I think this guy musta been waaaaayyyy out on the trails. For a long time....I will say this for him, he was VERY creative in the way he "fixed problems". I don't think he ever got around to doing them right, later, though.

 

[Joe321]

I still couldn't find the relay, got any pictures from your own personal truck?

 

[unoleisu]

I'm sorry, I don't have photo capability at the moment. but.....
As I said above, the book says it is on the harness on the passenger side of the engine compartment. It shows a drawing that illistrates it is mounted inside the passanger compartment below the glovebox, mounted on the wall next to the passanger door. This is on the harness for the ECA computer. Now.......

This harness passes thru the firewall. It travels along the passenger side fender behind the air filter. The Starter Relay is on this harness.

I found that MY EEC power relay is actually mounted exactly behind the air filter (NOT on the wall under the glovebox, as the book said.) Same harness circuit, but easier access.

Starting at the battery, moving toward the firewall along the top of the fender well, I found the Starter Relay next, then the EGR valve (lower on the fender) then the Fuel Pump relay (mounted on a little bracket, the connector was green, relay was a square black box) Then a little further, I found the EEC Power relay (mounted on a similar bracket, BROWN connector, relay was another small black box about 1" square) all the wiring colors were as I said before.
Hope this helps!

 

[84bluebronco2]

I know you said you have been through all of the electronics, but would this year 2.9 happen to have the famous TFI module?

 

[Joe321]

TFI? I do believe it says 2.9L EFI on the intake, so no don't think it's the famous TFI model.

 

[greasemonkey6886]

If it says 2.9 EFI on the intake it should be. TFI refers to the ignition module mounted on the back of the dizzy. Most of the are grey in color and are a rectangular plastic "box" with a wirinig harness plugged into it. These are notorious for going out at the worst possible moment.

 

[84bluebronco2]

+1 to greasemonkey. My TFI decided to go out halfway through bleeding my clutch on the old B2. It will result in no spark. Engine will crank freely, fuel pumps and everything will seem normal, but still no starting.

 

[adsm08]

ALL 2.9's had the infamous TFI module.

The module itself it actually a pretty sturdy piece of primitive electronics. Aside from being short a pin and having a different calibration they are identical to the fairly trouble free units used on the small blocks. The issue on the 2.9 was placement. They were put in a terrible spot.

 

[84bluebronco2]

As is said almost every time adsm posts, +1. I have had a 2.8 and 4.0, and wasn't positive about all 2.9's or only certain years having TFI.