Ford Mustang Forums banner

So I did the GT fog light/relay fix..

2K views 7 replies 4 participants last post by  CaliNotch n MI 
#1 ·
I did the 87-93 GT fog-lights fix (Mustang GT Fog Light Fix) and it worked great for about two years but now I keep instantly blowing the 15amp inline fuse that was added to the system. I had another relay & headlamp switch laying around but neither of those fixed the problem.

Any ideas? Multi-function sw?
 
#2 ·
Have you checked your MFS at this point for melting? Also make sure the thick B/O fuselink that starts at the starter solenoid (relay) isn't grounding out somewhere. If it would, it could most likely be where the harness enters the driver's side firewall. From there it branches off to the headlamp switch and the EEC relay.

Check those areas and let us know what you find.

Sent from AutoGuide.com Free App
 
#3 ·
Finally got around to checking it out.

MFS plugs look good. I even popped in another MFS and still blew a fuse. Wire off the started relay looks good on the engine side, I'll poke around under the dash side.
 
#5 ·
In the February, 1991 edition of Popular Mechanics, the "Car Clinic" by Mike Allen had the following:

"Ford TSB 89-17-11 says this is caused by overheating in the headlamp circuit. It's a phenomenon affecting '83-'89 Escorts, '83-'87 EXPs and '87-'88 Mustangs. You'll need to replace the headlamp and dimmer switches, several connectors, and then bypass the wiring in the circuit with new 12ga wire run alongside the original harness. It's supposed to take 1.3 hours for a service technician to do this, and you ought to see if the dealer will still do the repair under warranty."
 
#6 ·
I ended up finding my problem.

I plugged one fog light in at a time and the fuse only blew when the drivers side was plugged in, so it ended up being a grounding issue with the bulb.
 
#8 ·
Someone used it and didn't return it...
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top