The Stovebolt Site Forums The Shop Area The Electrical Bay No stop lights no horns

HI...parking lights work...turn signals work...bulbs new...stop light switch depreses...fuse ok..but step on brake no stop light I got it this way from PO who painted all the wires black on the firewall...push horn button and all I get is a tump tump noise...HELP! Thomas Edison I'm not..we thank you for you time, Steve

Could be that the stop light switch is dead. Does it have a mechanical or hydraulic switch?

Also you wouldnt believe how dirty connections and rusted grounds will make things not work. Take a little time and follow some of the wires and make sure there arent any broken or loose connections.

I got ****** at mine and decided to just rewire the whole darn thing. Works good now!

A new wiring harness would probably be a plus. Ditto on rustednuts advise of checking all of your terminals & grounds. You can use a multi-meter to check your brakelight sending unit. If you get power in but not out the sending unit is bad.

Get a test light & start traceing the circuits. Like Tiny says one term on the stop light switch is hot all the time. When the pedel goes down the other term. should be hot. I don,t know about tump tump but if you get a clicking noise under the hood when you press the horn button it means the circuit is good up to the relay. Again use the test light to see vif any curent is getting to the horn. If not it,s a deffective relay. If it is it,s a bad horn.

Start simple, check for bad grounds. Ground the bulb case while someone else depresses pedal. Or use alligator clips to ground if you don't have help. Ditto on the horn, especially with painted wires etc. Good luck.

Could also be a bad turn indicator switch. Usually the wire goes from the brake light switch to the turn indicator switch, then to the lights.

Sounds like bad grounds to me.
Pick up an electrical test probe light(ice pick with a light)at the parts store. and start checking your taillight wires,etc..... from the firewall back.
bet its ground wires!!!
Marty
(you might want to run a ground wire straight from the batt. to the frame/body)

Regarding the breaklights, if the turn signals work then the ground should be fine (same filament). I would look to the switch or the turn signal switch may be killing the stop lights as baldy said. You might try jiggling the turn signal handle with the brake depressed while a victom watches for glimpes of light.

The horn does sound like a ground or a bad horn to me. You can make temporary grounds to test this theory. Just give it a new ground using a clip jumper. If you don't have one, make one as this is a great diagnostic tool to have in a shop (12gauge wire with clips at either end). Just clip one end to the ground on the horn, and the other to a good clean metal contact. If it is still weak (thumps) then see if the power side is good enough with the same manual jumper (battery to pos side of course). If it works then, you'll have to look to the wiring inbetween somewhere that is weak.

What Kind of vehicle?? On some cars/trucks the power for the Brake light switch comes out of the Headlight switch not the fuse-block.

you need a test lite and a friend with some ele skill,,,,your thump if coming from horn you need horn,,,brake lites if there are turn signals or no turn signals...doc

What year is your truck?

In this discussion it would help a lot to know if it has factory turn signals or an add-on, and if an add-on is it a four-wire or a seven-wire?

OK...sorry 1954 3100 rewired to 12 volt by PO nice job....add on turn signal switch lousy job...ground seems fine as lights work. I will check the stop light switch I did not know that one side was always hot..its the old lever mechanical type. I will make that clip jumper and jump out the horns to see if they even work...can I go directly to the battery for a split second? steve

if turn sig is wired as it should be brake lite works thru turn sig so you mite have a prob in the turn sig sw wiring..see if you can get a wire dia for it...doc

Could be the dimmer switch has a bad connection...after putting in a new wiring harness we found out that the connection in the dimmer pedal was bad...had to do a little wire brushing the terminals....everything works now...I turned my parking lights into turn signals...just waiting on a new radiator....last part..