Electrical: No brake lights

[RareBird]

Turn and tail lights working great but now brake lights not working. Wiring harnes is new as well as booster and switch. Is there a seperate fuse or might I have a defective switch on the Hydravac?

[Gunslinger]

Avantis have a separate brake light fuse...your car may well be the same.

['66Commander]

Check the switch connected to the bottom of the Master Cylinder. It might be clogged, or the leads on the switch might have corrosion on them (Or maybe they're backwards?). My switch has some gunk in it from the old Master Cylinder and had some corossion. But once I knocked those out, I was good.

[(S)]

Brake lights and dome lights are on the same fuse. If you have power at the dome light, the fuse is fine. You can check a stop switch by using a jumper wire. Unplug the 2 wires and jump them together. If they light up, it is probably the switch.

[RareBird]

Now that you mention it the headliner was just installed and I noticed that the dome wasn't working, but I hadn't checked the bulb yet. Going check it out as soon as I get home. Thanks guys!!

[studegary]

Check the switch connected to the bottom of the Master Cylinder. It might be clogged, or the leads on the switch might have corrosion on them (Or maybe they're backwards?). My switch has some gunk in it from the old Master Cylinder and had some corossion. But once I knocked those out, I was good.

How can the leads being on the incorrect terminals ("backwards") matter at all? It is simply an open or closed switch. Either power goes through the switch or it doesn't.

[studegary]

Now that you mention it the headliner was just installed and I noticed that the dome wasn't working, but I hadn't checked the bulb yet. Going check it out as soon as I get home. Thanks guys!!

It may not be the bulb. It may be a spot on the wire touching a ground causing the fuse to blow. Lets hope that you do not have to pull the headliner.

['66Commander]

How can the leads being on the incorrect terminals ("backwards") matter at all? It is simply an open or closed switch. Either power goes through the switch or it doesn't.

I'm not sure. I've always kept mine marked where they go. So I haven't tested to see if it would be a problem or not.
Just a suggestion.

[3rdGenStude]

Brake lights and dome lights are on the same fuse.

Where would this fuse be located on a '62 GT? I recently developed a problem where jumping the brake switch wires no longer lights the brakes up. Somewhere in the rats nest of wires under my dash I assume?

Paul

[RareBird]

I jumped wired to bt pass the switch and brake lights work. I can only locate 2 fuses and a flasher on the far left part of the left side of the dash. Is that all there are? Fuse seemed to be blown so I replaced it but still no lights. Also I disconnected wires to dome but still nothing. Your thoughts??

[3rdGenStude]

Rarebird,

In your case, it sound like your hydraulic switch is bad. Right now, my booster is plumbed out of the line, and I was happy just to have the lights work if I crossed the wires. Somewhere along the line, that has stopped working for me.

I have a new Harley Davidson switch hooked into the newly rebuilt booster, since the Harley Switch is supposed to work with DOT5 fluid, which I'll be using when I get the new lines and cylinders in. The Harley switch is physically smaller, and uses a different style electrical connector which I've already wired in while redoing the crisply wiring in that area of my engine compartment. I made a couple little electrical adaptors to work with the old hydraulilc switch which is just plumbed right into my brake line. But that old switch is apparently dead. Either that, or I have a blown fuse.

I found an original style hydraulic switch at my local NAPA. Identical to the original, except shiny! Otherwise, I know SI has them, too.

Paul

[jimmijim8]

Test 1 If you take the 2 wires that are plugged onto the pressure switch test terminals and join them together with a jumper lead. Your brake lights will come on unless a fuse has been blown or not in place. If you pass test no.1 go on to test no.2>>>>>>>>>>>>>>>>>>>>>>>>>>>>.Test no.2>>>>>>>>>>>>>>............. If you put the lead wires back on the switch and hit the brakes and the lights don't illuminate/your pressure switch is bad or your wires to switch terminals are not making a good contact. It does not matter which wire goes to whatever terminal.l. 1 of those wires should measure either 6 or 12 volts to chassis ground. Providing the fuse and circuit is complete. Key on or off does not matter. cheers jimmijim

[RareBird]

It was a new switch gone bad. Put another new one on it and problem solved. Thanks for your input!