Brake lights not working

[CATCHALLBLUE]

Ok folks my brake lights are not working. Can someone provide the wiring diagrams? Do i start with fuses? wires? bulbs?

'69 c30

Thanks

[FirstOwner69]

Originally Posted by CATCHALLBLUE

Ok folks my brake lights are not working. Can someone provide the wiring diagrams? Do i start with fuses? wires? bulbs?

'69 c30

Thanks

Start by running a good ground from the frame to bed. Or platform, if your truck is the one in your avatar.

[YourBuddy'sTruck]

I'd go for the fuses for easy fix. Bulb next.
If they're fine, its your wiring.
It'll be something simple guaranteed.
Remove your grounds and clean'em? If that's not it....keep digging.

[68gmsee]

I fought rear light problems on my 68 for about a year. Mine turned out to be grounding. As mentioned above check your wiring, check your fuses and install ground straps. The rear lights, and even front lights rely on a good ground back to neg battery. Years of grime and rust on bed bolts cause loss of ground path.

I installed 5 straps I bought at local auto parts store. I put a new one in back of engine to cab, one from cab to frame, one from bed to frame. I also installed a ground from the engine to frame, and radiator support to frame.

Remember there has to be a good uninterrupted path to battery negative from engine, cab, bed and radiator support. Don't trust old bolts.

[CATCHALLBLUE]

Thanks for the advice guys!

I doubt this ole girl is grounded properly so i'll get on that ASAP....

Just checked the fuse box and some of the connectors seem to be rusted, including the break light fuse....could that be causing the problem? Whats the best way to clean the rust off?

Does anyone have a good source for the glass tube fuses?

thanks again!

[CATCHALLBLUE]

Heres some pics

[bigmac73]

if you have a dremel with a small wire brush or a stone I think that would clean them up

[luckyss]

I had this issue once on my truck years ago, after may wiring diagnostics it turns out the brake switch was adjusted wrong and wouldn't release. Simple fix

[srvivor71]

Originally Posted by luckyss

I had this issue once on my truck years ago, after may wiring diagnostics it turns out the brake switch was adjusted wrong and wouldn't release. Simple fix

I had the same problem with my brake light switch. It's a cheap part but working on it at the top of the brake pedal linkage under the dash is a bear! I don't fit well up under the dash anymore.

[AirSpeed]

You can get fuses at any parts store, my local safeway grocery even carries them.

[67 chevelle]

got a wooden bed ? they are notorious for ground issues , especially when they have 40 plus years of corrosion

[Tinkermc]

Was your truck a flood victim?

[davepl]

Originally Posted by AirSpeed

You can get fuses at any parts store, my local safeway grocery even carries them.

But you're in California. That'd be a hell of a drive to buy a fuse. Shop locally instead.

In all seriousness, grounds are indeed the most common issue. And I will do the next line in all-caps with apologies, but:

YOU MUST TEST IT UNDER LOAD

I've seen soooo many people hook up a volt meter, see 12.7, and think it must be fine. But then you put a load on it and the resistance due to the bad ground (or wire) will show it drop to 7V or something. That's not the case here, because they're just off and not dim, but it's a good reminder.

Ground issues are extra-common in a case like mine where I've powder-coated everything. So I've run extra group straps, extra ground wires, used a lot of Star washers and tried to be good about grinding paint/powdercoat off important ground points.

[CATCHALLBLUE]

Originally Posted by 67 chevelle

got a wooden bed ? they are notorious for ground issues , especially when they have 40 plus years of corrosion

yep genuine antique rotted wood bed. Most of the bed is in pretty good shape. mostly bad near the cab. There was 2 layers of plywood on top of the bad protecting it.

Been rolling around under the truck and only found 1 ground under the passenger door connecting the cab to the frame.

Got some work to do

[CATCHALLBLUE]

Originally Posted by Tinkermc

Was your truck a flood victim?

Ya it looks pretty grisly in that picture doesnt it? The front end was sticking out of a garage by a nose for years so im sure moisture got in there.

[67 chevelle]

run a good ground wire from your frame to the back panel under the tailgate , I bet they start working

[CATCHALLBLUE]

Ok y'all here's my ground straps so far....

under the front passenger fender to frame


radiator mount to frame


rear passenger side frame to bed


and this is where im stuck. from the valve cover to the firewall. I cant find a hole/usable screw to attach too. Does this valve cover ground look ok?

[Mr Chevorlet]

I would say your fuse box would be the first indication why there not working, but the ground wire would be good to have also.

[71K20chevy]

Good grounding fixed my taillight problems.