My nephew has a '89 F150 4x4 4.9 5 speed beat up country boy truck. I gave him a battery to install, out of a Dodge Neon, with reversed battery poles. Of course, he installed the cables to the wrong poles and the starter solenoid started smoking when he attempted to start it. He installed a new solenoid and it cranks, but no start or fire. All accessories seem to work, interior lights, etc., but the check engine light stays on with the key out of the ignition. I located five fusible links in front of the solenoid running to a loom next to the battery behind the right headlight. I suspect he cooked a link.

A yellow wire running from the solenoid to the loom behind the headlight appears to have two fuse links on it. They look a little distorted, but I have not checked them with an ohm meter.

Can anyone give me a clue of how extensive the damage may be? And where to start?

 

He most likely fried the computer. That's why the check engine light is stuck on. You need to unhook the battery and check ALL those fusible links. Use a multi-meter set to either the continuity setting or the ohms setting. You should have NO resistance (the meter will swing all the way to the right, or it will read 000 on the display)between the two ends.

 

did he not notice the sparks when he was hooking it up?

 

Doesn't matter about the sparks, by the time he turned the key, most of the damage was done. I've read in other posts that it could be as simple as a single fuse link, but other posts talk about ECM damage. I also thought I would find an underhood fuse box on this truck on the driver's side, where there may be a pair of heavy fuses, 60 amp or so. I don't find a fuse to check under the hood. Any hints there?

 

Found that the large green wire from the starter solenoid to the alternator was burned before the 10 gauge fuse link going to the alternator. I soldered that wire and it still cranks and the plugs fire, but won't start. Found the frame mounted fuel pump under the driver's seat area, and the pump does not run with the ignition turned on. I pulled the fuel pump relay off, turn on the ignition and found 12 volts on one of the wires, but only one. Now I need to figure out why the fuel pump won't run. No fuel pump fuse on a '89 F150?

 

<i>No fuel pump fuse on a '89 F150?</i>


Yea, fuseable link/s.

 

If I had a bad fusible link, would I still be getting 12 volts at the fuel pump relay? I looked at all of the fusible links in front of the starter solenoid and they all LOOKED fine. I pulled back all the tape and plastic from the wire loom looking for a butt connector, but they are hard-wired into the harness. The only way I can test them is to cut them out? My experience with fuse links is that if they are burned, you can really tell because they will look burned and bend very easily.