# convertible top switch



## extinctmake (Feb 8, 2011)

I have to replace the convertible top switch to my '65 GTO. The yellow wire on the switch that goes through the firewall and connects to the junction block on the firewall separated from the switch.

Upon removing the old switch etc. I realized there isn't a fuse associated with the power top circuit. Nothing on the fuse block and no inline fuse.

A friend of mine suggested that I put an inline 20 amp fuse in the yellow wire between the junction block and the switch. It is a 10-12 gage wire and I can imagine it is a hot circuit.

Has anybody done this before? It would seem to be a way of protecting the circuit as well as the rest of the wiring harness. Maybe this is protection that isn't necessary either.

Any thoughts?


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## geeteeohguy (Feb 2, 2008)

I'm running mine stock, no fuse and no relay. A lot of guys are running a relay in the circuit to help take the load off of the switch, which seems like a great idea. That motor pulls a lot of amps. I'd do a relay before doing a fuse. The switch usually burns out over time due to all the current going through it.


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## extinctmake (Feb 8, 2011)

Yeah we were discussing the matter over beers tonight. I can't complain because the power top switch is one of the hold over parts from when I restored my car. It lasted nearly 50 years.

I think I will incorporate a relay instead of a fuse. That idea cropped up a well. I think having some sort of protection in that high amp circuit will serve as some insurance for the rest of the electrical system on this buggy.


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## Rukee (Feb 8, 2007)

Why not do a relay and a fuse on the input load end of the relay?


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## oldgoat64 (Jun 26, 2014)

I was a lot surprised to find out what you did, no circuit protection. I ran mine for 20 years that way with out a problem. I replaced the top motor with one out of a 90's Mustang pump 10 years ago. 
I have been updating the wiring on my car & decided to go to the wrecking yard and cut the relay assembly out of the mustang. Now the car has an up & down relay and a fuse & a circut breaker. It does work a lot better


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## geeteeohguy (Feb 2, 2008)

It shouldn't work any 'better', as current is current. It should, however, work a lot longer with a relay to protect the switch. Relays are a good idea here.


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## extinctmake (Feb 8, 2011)

Alright, I got a new switch from Ames and installed it. It works fine. I haven't done anything to the circuit just yet, but I did notice something that lends some confusion to this issue.

I was flipping through the new Ames catalogue that accompanied my new switch and noticed Ames lists a 40 amp relay for the power top. This made me wonder if the junction block I mentioned in my initial post is in fact a circuit breaker or a relay. 

The only wires that go to this part is the pig tail from the battery cable and a wire from the power top switch. The replacement relay Ames lists looks identical with the exception that it has an individual terminal for the battery cable pig tail and the other for the wire from the top switch.

I cannot fathom this car was manufactured without any kind of circuit breaker/fuse/relay for a power top circuit. A relay would not provide any kind of protection, so I am still contemplating adding a fuse and/or breaker to the circuit.

Any insight?


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## geeteeohguy (Feb 2, 2008)

These cars were manufactured just as yours is. Straight wire, with no fuse and no relay. A relay will protect the switch, big time. The relay passes the heavy current, the switch just activates it. Without it, the switch handles all the heavy current. But, it was built without a relay or a fuse. Remember, when these cars were built, they were expected to last 8-10 years.....not 50.


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## extinctmake (Feb 8, 2011)

That's what I was afraid of. So it is just a junction block on my firewall. I will have to put a circuit breaker or something to protect the circuit. 

Maybe a good fix would be to replace the junction block with the 40 amp relay Ames has in its catalogue for a mere $24 (part number H139J). It looks identical to the junction block on my car with the exception that the Ames relay has two stud terminals instead of one. 

Thanks again


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## LouCabra (Jul 20, 2015)

*Progress of fuses and relays?*

I know its been a while, but Id like to know how this story ended up. I recently bought a 68 convertible with the top switch missing. There was just a toggle switch drilled into the bottom of the dash. the power is coming from the open blade in the fuse bow, which, I think just connects to the battery. I got the new switch from Ames and have no idea where the pose is supposed to come from. I can't find anything that might have been original.

Got and pictures or diagrams of how y'all wired in a relay land/or fuses? I'm still getting up to speed with working on these cars after a 30+ year hiatus.

Thanks


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