The Stovebolt Site Forums The Shop Area The Electrical Bay No brake lights on my new Stovebolter

Hi All,
I am the very proud owner of a new (to me) 1955 C3100 first series that I drove home today form the buyer ( 35 miles away) — He pointed out that the brake lights did not work, so I drove home with the flashers and now am set to repair this problem and get my plates and get on the road.

I have the following situation
• Brake lights do not turn bright upon any braking — both sides
• Tail lights are single bulb — both sides
• Turn signals work in tail lights — both sides
• Tail lights turn on when light switch turned on from dash
• All other lights work as normal ( Front headlights, front turn signals)
• The two wires leading to the brake light switch have battery voltage when I put one lead on one wire and other lead on other wire

The above symptoms point to a bad brake light switch to me, as I am new to this truck and I don’t know the circuits that well yet. The switch appears to be mechanically grounded when the brakes are not applied, via a lever that moves with the brake pedal which contacts a extension on the switch. While I was at the local auto parts store, I asked if they could get it and they said they would have it tomorrow and it is $20.

I am assuming that since the tail lights work, that are properly powered and that since I see 12V (13.5 actually) between to two wires that connect to the switch, the switch is never closing between the two contacts. One last test I was going to do before running out of time and daylight was to make a jumper between the two wires going to the switch to bypass it as they are simple female “banana” style connectors — I did have some concern though that the switch may also have a current limiting resistor in it, so I also decided to wait on the shorting jumper until I could ask here, so I would not pop the bulbs in the back — I do not know yet how hard getting those bulbs in the back will be to get ( are they 1157’s?)

Anyways, I would appreciate the thoughts of the many smart readers here and especially suggestions as to other tests if needed in your opinion. These darn brake lights are stopping me cold from enjoying my new baby. Image of the switch I see on the firewall (directly below steering column) matches the image from Orielly auto ( URL below)


http://i157.photobucket.com/albums/t49/JoeStine/brake%20light%20switch_zpscec5tcns.jpg

Any help or suggestions would be most welcome

Joe

Stop light switch is a simple on-off switch. When brake is depressed the switch transfers the 12v on terminal from light switch to terminal going to lights. With an ohm meter between the switch terminal (no wires connected) it should go from infinite to 0 ohms as you move the lever open and closed. If you short the wires together you should get brake lights.

http://chevy.oldcarmanualproject.com/shop/1955truck2/55ctsm1202.htm

Joe,

Your method of testing is just fine, if you have voltage across the two terminals with the brake pedal up and down, then the switch is staying OPEN and is bad.

If you didn't depress the pedal then you only did half of the test and the switch condition is still unknown.

You're ok to use the shorting method, you will not hurt anything as long as you don't go to ground with the jumper wire.

Mike B

A test light is your greatest tool for electrical work. $5 or less. The switch is down on the engine side of the firewall down low by the brake pedal shaft. Ground the clip of the test light & insert the prod into the terms. one at a time. Put the test light on the 2 terms. One should be hot all the time. Press on the brake pedal & both should be hot. If not the switch is defective. It is held on by 2 screws from the inside. If the arm on the switch does not follow the brake shaft then it is obviously defective.

Hi All
Well, I got the original switch to work after I struggled for 3 hours getting it off. The lever on the original was stuck and I freed it up. I went to the local auto parts store ( Orielly) and had them order a replacement and much to my amazement, the replacement was a mirror image of the original ( lever on wrong side). I had a look at their parts screen and the new OEM AC Delco part they could have got instead special order and it was also mirrored. I looked on line and every place I looked had the same thing - the brake switch is now manufactured as if the original was mirror imaged, and will not fit unless two new holes in the firewall are drilled. Perhaps this is peculiar to my 55 first series 1/2 ton. but I was quite floored when I discovered this today

Check switches for a 1954, rockauto.com shows them with the lever on the left side closest to the engine. The switches shown for 1955 have the lever on the other side.

If you got your original freed up and it works, I would just use that one. The originals are tough. I have never had one go bad.
Carl