Stop Light switch problem

B

bobd

Junior Member
I replaced the stoplight switch on my 30 pickup. The lights are hooked up thru a 30Amp fuse. Every time I put the brakes on the fuse blows. There are no shorts any where, the switch is not shorted either. I can't figure this problem out. I've fixed a lot of electrical problems but this one has me stumped. Any one have any ideas.
 
Some of the repro 30-31 brake light switches on the market are very poor quality. Most don't even have bushings at each end and are prone to shorting out. For a very good quality one purchase from A&L. They are made just as Henry ordered.

A&L, Canton Center, CT 860-693-0112

Tom Endy
 
Another little modification trick you can do once you get the current problem resolved is to bypass the light bale.

Henry, for whatever reason, wired the power to the brake light switch from a power buss inside the light bale. The light bale, which is a common source of problems that can blow the fuse for a number of reasons, has no function concerning the brake light, only the tail light.

If you are on a tour and a short in the light bale blows the fuse you can disconnect the wire from the generator or alternator that runs down and powers the bale and continue driving the car during daylight, however you will not have brake lights, which is illegal and definitely unsafe.

The modification is to remove the wire that comes from the bale that is attached to one side of the brake light switch, fold it back and tape it off to insulate it. Run a separate wire from the fuse to the brake light switch and it will make it independent of the bale. Then in the case of a problem with the bale you can disconnect power to it and still have brake lights.

Tom Endy
 
I had an aftermarket switch on my huckster and when I put on the brake, same problem. The problem was that it pulled the shaft thing all the way through the switch and shorted on the body of the switch. I adjust the position of the switch so the shaft did not put so far through the switch and has worked fine since.
 
Bob, your switch will be different than Fred's. Yours may be shorting out like his, but the 29 switch is pulled to activate, and the 30 is pushed. He can also adjust the position of the switch, and you can't.
 
700rpm said:
Bob, your switch will be different than Fred's. Yours may be shorting out like his, but the 29 switch is pulled to activate, and the 30 is pushed. He can also adjust the position of the switch, and you can't.
Click to expand...

Isn't the 30-31 pushed to deactivate?

Bob
 
Thanks for all the ideas. So far I have by passed the switch. It doesn't blow the fuse when by passed and have ordered another one from Mikes. The funny part is there is no shorts showing any where on the switch. I'm going to pull it out & hook it up to a battery to check it out further & see just what happens when it has voltage put to it & the switch activated. Maybe I can get a better idea of what is happening on the bench.
will let you know what I find.
 
Guesse I am not understanding this. It was posted above by a good source that A&L sell the good one, so you ordered one from Mike's. I am guessing this is where you bought the defective one. Just an observation from afar, no insault intended. Rod
 
Well, I guess Brentwood Bob and I misremembered that. I gotta go look at my '30 and get it right in my head. :confused:
 
700rpm said:
Well, I guess Brentwood Bob and I misremembered that. I gotta go look at my '30 and get it right in my head. :confused:
Click to expand...

The 28-9 brake switch is just the opposite, as the link pulls the switch to the on position, and if the brake pedal goes too far down, it can pull the repro switch rod into the housing.
 
bobd - sounds like you need a helper or long meter leads to have hooked up to the switch (wires and battery disconnected - have it on the OHMS or resistance setting) terminals and press the brakes as you normally would while sitting in the seat. Should see infinite with foot off the brake and as close to zero (anything less than an ohm is good) with brakes on and shouldn't flutter around much. With them on push the brake pedal harder as if in a hard stop and see if it stays at zero.

Then have one wire of your meter on the frame ground somewhere and the other meter lead to either of the terminals. Press the brakes as you normally would and press harder as if in a hard stop, should read infinite. If it doesn't you got a shorted switch to ground (poof goes the "imaginary" fuse) if it DOES read infinite try the other switch terminal. Should still be infinite with the brakes on.
 
Rowdy said:
GuessI am not understanding this. It was posted above by a good source that A&L sell the good one, so you order one from Mike's. I am guessing this is where you bought the defective one. Just an observation from afar, no insult intended. Rod
Click to expand...

^^^^^ this

The switch that A&L sells is not cheap but neither is quality. Maybe Mike's sells the A&L unit I don't know. Buy the good stuff!
 
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