My 1970 Mach 1 with FMX Transmission kept blowing the fuse labeled Radio/BU. This also disables my turn signals. I really would like to get my turn signals operable for obvious reasons. I finally narrowed it down to the fuse blowing when I put it in reverse. I thought I would be smart and unplug the harness to under the hood. Works great for the blinkers, but disables the Neutral Safety Switch, preventing the car from starting.This switch/harness is currently unavailable in reproduction. Is there a way to unplug the harness, disabling the Backup Switch, and put a jumper between the contacts in the plugto make the circuit complete for the Neutral Safety Switch? Any other solutions? I would appreciate any help I can get from anyone who has encountered this problem. Thanks.

 

My first suggestion, try a slightly higher fuse (if possible), something like 5 amps might make the diffference. Also try looking for any corroded or exposed portions of wire that could be causing this.

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Thanks for your help. I am slowly narrowing the problem down. I found that I had L1156 bulbs in the backup sockets. That is the bulb called for in the NPD catalog for a 1970 backup lamp. L1156 is a single terminal bulb. I looked in the sockets and found that they had two terminals. I removed the bulbs, and my turn signals work fine now. I also looked in the catalog and found that 65-68 Mustangs used L1142 backup lamp bulbs. This is a two terminal bulb. I don't know if I've got '68 backup lamp assemblies on my car or not, but I am going to get some L1142 bulbs and see if I can get my backup lamps working. Thanks again, bobbycjr.