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I am just about finished with a 4 year frame off resto of a 78 Vette. One of the last things I did was remove the steering column to replace bearings and adjust/lube the lock. Prior to the column removal all lights worked flawlessly. I put the column back in the brake lights no longer work. Brake light switch is new and works fine. I checked the white wire on the steering column connector and it is dead, no power. All fuses are good. Turn signals work fine. Where do I look now?
have you checked for 112 volts at the brake light socket??
have the wiring harness been touched in the rear of car, or in the interior going back to the rear of car??
have you checked for 12 volts at the column going to the brake light circuit??
what have you checked and with what did you use, test light or meter or what? grounds at rear of the car bad?? what besides the column have you done electrically to the car???
Every test was done with a test light AND a volt/amp meter. There is no power to the brake light switch (orange wire) and no power to/from column connector (white wire). All turn signals work as do the tail, tag, marker, and backup lights. The brake lights worked fine before I removed the steering column. Double checked all grounds and all are good. Only thing done electrically at this point is installation of an electric radiator fan and an electric fuel pump. Both are on new fused circuits direct from positive side of battery.
Every test was done with a test light AND a volt/amp meter. There is no power to the brake light switch (orange wire) and no power to/from column connector (white wire). All turn signals work as do the tail, tag, marker, and backup lights. The brake lights worked fine before I removed the steering column. Double checked all grounds and all are good. Only thing done electrically at this point is installation of an electric radiator fan and an electric fuel pump. Both are on new fused circuits direct from positive side of battery.
Is the connector at the steering wheel (large one) together correctly? Is the white wire connectors seated correctly? If you have no power at orange you should and it comes from fuse. You checkef both sides of fuse and made sure the tabs are not corroded.
Last edited by henrikse; Feb 15, 2018 at 02:09 PM.
Reason: add line
Checked all fuses at the tabs and all are good. No power at the orange wire on the stoplight switch. Tried a jumper wire to the switch and still no go. Switch is good but still no power at the white wire on the connector. Unplugged the connector and tested both parts - no power on either side. Purple wire on connector (turn signal) was hot. I have not checked the schematic. Not sure if it goes thru the brake light switch before or after the connection under the column. Will study the schematic tonight.
Checked all fuses at the tabs and all are good. No power at the orange wire on the stoplight switch. Tried a jumper wire to the switch and still no go. Switch is good but still no power at the white wire on the connector. Unplugged the connector and tested both parts - no power on either side. Purple wire on connector (turn signal) was hot. I have not checked the schematic. Not sure if it goes thru the brake light switch before or after the connection under the column. Will study the schematic tonight.
If you have no power on your orange wire that is your problem. Attached schematic I found online. You have to get 12+ on the fuse and then follow to the orange wire. It has to be there to work, You said you jumpered so are you saying you ran a jumper from 12 volts to the brake light switch (white) and the lights did not come on? If so you have multiple problems.
OK, I studied the schematic and then ran several tests with these results:
-Positive/feed side of flasher socket on fuse box: 12+ volts
-Positive/feed side of brake light switch: 12+ volts
-Outlet side of brake light switch (plunger out): 0v
-Outlet side of brake light switch (plunger in): 12+ volts
-White wire on dash side of “harmonica” connector (brake switch plunger in): 0v
-White wire on column side of “harmonica” connector (brake switch plunger out): 0v
-Turn signals work.
-Hazards blow fuse when hazard switch pushed (tried three different flashers).
-Have no idea where to check next. Could it be the turn signal switch????
You do have 12 volts on the ORANGE wire that goes to the brake switch at all times as long as the battery is connected correctly
Then...when the plunger of this brake switch is IN....you should have 0 volts on the WHITE wire. Because this it the position it is in when the brake pedal is not being pressed....correct???
When the plunger of your brake switch is out...like when you press your brake pedal far enough ...it should have 12 volts on the WHITE wire (or whatever your battery voltage is at that time if the engine is not running.
Knowing that from the schematic that the WHITE wire goes to your turn signal switch. You should have 12 volts when you press your brake pedal...and 0 volts when you are not pressing the pedal.
SO...if you are getting the correct 'switching' of the voltage being there and not there at the brake light switch connector...but it changes at the connector for your turn signal switch connector. Then there is part of your problem. The WHITE wire in the harness is cut or damaged some how. I would disconnect the turn signal switch connector and verify that the WHITE wire is getting the correct signal from the brake light switch when it is IN or OUT.
From what you wrote you stated that the turn signals work perfectly. Have you tested this when the headlight switch is also pulled to light up your running lights and check your turn signals???
YES...it is possible that the turn signal switch is not good. The hazard switch portion of your turn signal switch when pushed in can be literally grounding out that circuit...causing it to blow fuses instantly.
Disconnect the turn signal connector and OHM out the BROWN wire on the column side of the connector and have the other end of your ohmmeter touching KNOWN good ground on the column. When the hazard switch is NOT pressed in you should see infinity. Or what ever the screen on your ohmmeter looks like if you have not connected the two probes.
When you push IN on the hazard switch...it should also be like it was in the past test.
BUT...if you do see a change and you actually have an ohm reading...then this is telling you that the switch is allowing that cirucit...which would normally NOT have any value ( positive or negative) to now show up being grounded out....becasue your to the other probe is going to a ground.
Rechecked everything with a multi-meter and test light & here are the results.
First as a reminder everything worked fine before I removed the steering column to replace the lower column bearing and rag joint.
-Battery - 12.6V (checked at battery, starter, & fuse box)
-All grounds good (additional grounds have been added)
-Positive/feed side of flasher socket on fuse box: 12.6V
-ORANGE wire of brake light switch: 12.6V
-WHITE wire of brake light switch (plunger out): 12.6V (same at harmonica connector)
-WHITE wire of brake light switch (plunger in): 0V (same at harmonica connector)
-Front & rear turn signals work with head/park/tail lights ON or OFF
-Hazard switch blows fuse when pushed (multi-meter shows direct ground when pushed in)
-Horn works
Harmonica wires (column/switch side) (connector unplugged)
White (power to brake lights) – Multi-meter shows direct ground
Dark green (RR brake light) – Could not get power for test because of WHITE wire direct ground
Yellow (LR brake light) – Could not get power for test because of WHITE wire direct ground
Purple wire (power for turn signal) (0V because not plugged in)
Brown (power for flasher) – Hazard switch OUT – open circuit (0-V)
Brown (power for flasher) – Hazard switch IN - Direct ground
Dark blue (RF turn signal) – 12.6V (used jumper to purple wire for test)
Light blue (LF turn signal) – 12.6V (used jumper to purple wire for test)
Black (horn ground) – shows positive ground when horn is pressed (horn works)
All circuits/wires on body harness side of harmonica connector test true to turn signal wiring chart at post #13. The body harness side seems to work without issues.
It looks to me like the problem is somewhere in the column.
Cleaned and tested all the connections on the harmonica and all fuse box connections so all connections are good.
With connector open your white wire should not go to ground. Hand trace it to the brake light switch as it must be shorted before it gets there as the switch is normally open. Or else when you say brown wire in to flasher is ground follow this wire as well. It should not show ground Are the wires in the column loose or feel tight. The brown could be grounded inside. If you use an ohmmeter on the connector and to ground you can try to wiggle the flat ribbon going up the column to see if ground goes away.
Well I found the problem. While reinstalling the steering column I pinched some of the turn signal switch wires when I tightened the two upper steering column support bolts under the dash. Do I feel stupid. Now to figure out how to insulate the wires so they don’t short out. Again thanks to all for the help.
Heat shrink is the best way to repair although you have to be able to slide the tube on one end. If not black electrical tape wound tight will suffice. To use the heat shrink you can cut the wire , slide it on then solder the wire back together. WOuld not suggest connectors as they add resistance.
Congrats on fixing your car!
Well I found the problem. While reinstalling the steering column I pinched some of the turn signal switch wires when I tightened the two upper steering column support bolts under the dash. Do I feel stupid. Now to figure out how to insulate the wires so they don’t short out. Again thanks to all for the help.
Brake lights stopped working
