ORVette

Turn signals work. Flashers work. Switch ok. Fuses(STOP/HAZ, & round flasher plug fuses OK, including the one under the rear compartments, the one under the passenger dash, and the one on the fuse box). Have 12V to one side of the switch lead (unplugged). Gang connection under dash connected to steering column tight. Tried jumping the switch lead, nothing. Wires to the round plug in fuse under the rear comp.'s are yellow and white, and niether side has juice to it key on or off. Where do I go next? Thank you all for any help.

BLT-71

If I read this right. You pulled the lead off the brake switch at the pedal and had no power on either side. That lead comes from the panel and the panel had power. It has to be in that lead or connector that plugs to the switch.
Sometimes the wire is pulled loose of the contact.
.02

ORVette

No, I pulled the switch lead and I do have power to one side of it, I just mentioned that the plug under the rear compartments where the flasher fuse plugs in doesn't have any power to it. I don't really know what it's for, the flasher fuse for the turn signals is under the passenger side lower dash pad, and the one for the hazard flashers is on the fuse box itself, what's this third one under the rear comp.s for? Alarm? I'm sorta stumped here. I just don't know how evrything else can work and not the brake lights when there's power to the switch.

Pete79L82

If both turn signals work the the wiring to the rear of the car os OK as both the turn signals and the brake lights use the same wires.

If I read this right you have power to one side of the brake switch located near the brake pedal. It should be the Orange wire and it should be hot all the time. The white wire should only be hot when you press the brake pedal down. If it is not the the brake switch is bad. If it is hot when you press the brake pedal then the switch is fine. The next most likely part is the turn signal switch as the brake lights are routed though it.

Eddie 70

Just a thought here, I had something similiar on my 70 not too long ago. I had just replaced the brake light switch at the pedal, so I ruled that out. I checked most of the same things that you checked. So I got in the car and held the pedal down and had the wife watch the taillights while I worked the switch by hand, lo and behold the new switch was already laying down on me. Sometimes it worked and sometimes it didn`t. Another new switch and all is well.

ORVette

I'm pretty sure it's not the switch, because I jumped a wire accross the terminals on the plug, bypassing the switch, and still got nothing. The orange wire to the switch plug lead is hot all the time. I guess it could be something in the turn signal switch. Is there a way to test these switches? Thanks again for all the replies.

Pete79L82

At the turn signal harness connector at the base of the column, with the brake pedal pressed you should have power at the white wire. With neither turn signal on you should also have power at the yellow (left turn) and dark green (right turn) wires.

ORVette

OK-just went out and checked. White wire is hot all the time(actually, mine is black with a white stripe going into one side of the plug, and all white coming out the other side, green wire is green on both sides, and yellow wire is black with a yellow stripe on one side and all yellow on the other). Anyway, these are the correct wires you mentioned and side by side on one end of the gang plug. So, white is hot all the time, green-nothing, yellow-nothing. This is with the brake pedal depressed. Also, to make sure I had the right wires, I turned the key on and checked them each with the turn signals on and they showed power pulsing through them when their respective signal was activated.

To make a long story short, I'm not getting juice to the gang plug to activate the brake lights when the paedal is depressed, does this mean the problem is the turn signal switch in the column? Given that everything else checks out ok?

Pete79L82

yes, it sound like the turn signal switch. :cry

ORVette

Thanks for all the help. I'll get in there and probably just replace it. I'll post back when I get it fixed.

Pete79L82

Do you have a standard or tilt/telescopic column? I think the switches for the T/T columns are discontinued but some of the venders still have them. Watch out because the prices very alot $35.00 - $85.00 range. If you have the standard column the switch is still available from GM. gmpartsdirect shows them for $23.56 pn#1997988.

Turn signal switchs can be tricky to really diagnoise totally but from what you have posted I am pretty sure that is your problem. GM's manual say to diagnoise it "replace it with a known good switch."
Before you tear your column apart be sure to plug the new switch in first to be sure that is your problem.

The switches fit 69-79 without T/T or 69-76 with T/T.
Maybe a forum member has one laying around you could try before buying one.

ORVette

Standard column. Just went and got GM part #1997988, but the best they could do was $34. Good News! I can't tell you why, but this solved the problem. Funny, the new plug in wouldn't fit the one that leads to the harness without some finnessing. Double checked the part number and it's correct. After a little more looking, I found out that the aftermarket switch I replaced must've had some plug fit issues too. They had cut all the wires and grafted on the original AC Delco plug end to get it to fit the harness plug. Anybody need ten slightly used crimp connecters? Thanks again for all the help.