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1970 Mach 1 Backup Switch Help!

Old 12-03-2007, 06:36 PM
  #1  
bobbycjr
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Default 1970 Mach 1 Backup Switch Help!

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.
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Old 12-04-2007, 06:14 PM
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Clu7ch
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Default RE: 1970 Mach 1 Backup Switch Help!

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.

If you need, youmight find more help in the classic section, Click here!

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Old 12-04-2007, 07:59 PM
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bobbycjr
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Default RE: 1970 Mach 1 Backup Switch Help!

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.
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