Guest PetePontiac Posted April 30, 2013 Posted April 30, 2013 hi , my break lights and tail lights do not work, I checked the break lamp switchon the master cylinder with a tester and I do have power to the shortscrew but no power to the tall screw, I believe the short screw go to the tail lightswires according to my wire diagram, this car is a 1938 Pontiac " 6 " cylinderany help welcome,,maybe replacing the break lamp switch will help !!!thank you fellow car buffs
ply33 Posted April 30, 2013 Posted April 30, 2013 If you short the two switch terminals together the brake lights should come on. If they don't then the problem may be elsewhere. Alternatively, with your test lamp on the terminal with no power have someone step on the brake. The test lamp should come on if it is working.I don't know how many variations there are for hydraulic brake light switches but the one for my car is available in stock at my local better (non-bubble pack) auto supply store. I would guess yours is too. If you are careful and/or lucky, you can replace the switch without having to re-bleed the brakes.
Guest Drew Kreidelcamp Posted April 30, 2013 Posted April 30, 2013 If both the brake lights and tail lights are not working, the problem is more likely in the wiring to the tail lights along the frame, the light sockets or a bad ground. I think you could start by placing a jumper wire across the brake light switch and testing for voltage at the tail light sockets. If you have voltage, it could be a bad ground at the light socket or to the frame. It could also mean that the switch is bad. If you have no voltage at the light socket, the problem is in the wiring along the frame. A good visual inspection of the frame wiring might reveal the problem. If you see any wiring connectors, check for a loose fit or corrosion. On a car of this age, it is most likely a bad ground, a corroded light socket or an open circuit or dirty connector in the frame wiring.
Guest PetePontiac Posted May 2, 2013 Posted May 2, 2013 If both the brake lights and tail lights are not working, the problem is more likely in the wiring to the tail lights along the frame, the light sockets or a bad ground. I think you could start by placing a jumper wire across the brake light switch and testing for voltage at the tail light sockets. If you have voltage, it could be a bad ground at the light socket or to the frame. It could also mean that the switch is bad. If you have no voltage at the light socket, the problem is in the wiring along the frame. A good visual inspection of the frame wiring might reveal the problem. If you see any wiring connectors, check for a loose fit or corrosion. On a car of this age, it is most likely a bad ground, a corroded light socket or an open circuit or dirty connector in the frame wiring.Well it was not the switch. I did have my dash off then I installed it again, replace and connected thing back to were they belong. I had painted the dash under the out side dash.Thinking that maybe the light switch was not making a ground I sanded off the paint in the switch area. Well after I did that now my HEAD LIGHT blow a fuse.So it has to be some thing the light switch not being grounded correct!!!!!Just have to figure it out. thanks for your advise,, may have to have a mechanic come over and look at it. Pete
Guest Drew Kreidelcamp Posted May 3, 2013 Posted May 3, 2013 There should be no need for the light switch itself to be grounded. It should direct the current from the voltage source(wire from fuse box) to the headlights, parking lights, tail lights and instrument lights. The brake lights should be on a separate circuit. If any one of those light circuits has a short, the fuse will blow.
Guest PetePontiac Posted May 3, 2013 Posted May 3, 2013 (edited) On the light switch panel under the dash there is 8 connection for different wires,all the wire come to this box along with the fuses.I did have head lights, now when I turn on the head light on it blows the fuse.Could that switch be going bad or what ? It has to be some thing simple ...I had tail lights and head light before I removed my dash, after installing it now I have no lights. thanks for you input PETE. Edited May 3, 2013 by PetePontiac forgot something (see edit history)
Guest Drew Kreidelcamp Posted May 3, 2013 Posted May 3, 2013 To troubleshoot this, you might want to start by first identifying the voltage source wire to the switch. There should only be one hot wire with the switch off. Leave this wire on and remove all of the others. It would be a good idea to label the wires and make a drawing on a sheet of paper so you know where everything connects to. With the switch mounted in position, turn it on. If the fuse blows, the switch is shorted. If the switch is ok, reconnect one wire at a time and turn on the switch. If one of the other light circuits is shorted, it will blow the fuse when reconnected. Some older cars have the light fuse mounted in the switch. The voltage source wire will connect to a terminal on the switch which connects to one side of the fuse and the other side supplies the voltage to the switch circuit. If you know the switch is ok, you could place a jumper from the switch supply side of the fuse to the separate circuit lugs to isolate the short. This would make it unnecessary to remove the other wires.
Guest bofusmosby Posted May 4, 2013 Posted May 4, 2013 By this occuring after removing your dash, I would suspect that you have a pinched wire somewhere. Not sure how difficult it would be, but if you could float the light switch (just have it hanging with all the wires still connected) and see if this corrects your problem. If so, then you have a bad switch. I would also look closly at the light switch, to make sure that one of the tabs didn't get bent, and being grounded out.
Guest bofusmosby Posted May 4, 2013 Posted May 4, 2013 I see that you still have the original wiring on yours, like I have on my 37 Pontiac.
Guest PetePontiac Posted May 11, 2013 Posted May 11, 2013 UPDATE: Well I replaced the light switch and now no problems every thing think works finethanks all your you advice PETE:cool:
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