Brake wire? Need help
 

Alright guys long time forum follower but first time poster,
I've got a 1969 c10,
My buddy came over the other day and noticed something I never have,
Underneath the master brake cylinder the wire was broke,

He had a replacement one but had to get to work and now hes asleep so I cant ask where it connected to,
He just dropped off in my mailbox over night and thought I'd mess with it this morning

Anyone have any ideas?

Re: Brake wire? Need help
 

Sorry, no help. Just wondering why you are flipping us all off? :)

Re: Brake wire? Need help
 

Aha the pointer finger for men!

Re: Brake wire? Need help
 

Trace backwards from your fuel gauge’s brake light. This is the brake warning light switch that tells you when your brake circuits have been isolated because of a pressure differential (leak in one). I’m not certain where it plugs into your harness without looking, can do later tonight perhaps. Don’t be surprised if you have a brake warning light displayed persistently after fixing this- that’s usually why people cut them - and usually right before they sell them.

Re: Brake wire? Need help
 

Gotcha I appreciate it,

Got the truck nearly 3 years ago and never had any problems with it just the buddy noticed the wire was missing and stated he had another,

Il look into it further I appreciate it

Re: Brake wire? Need help
 

If you move the wire around, sort of in an arc, you might find where it plugs into. I have something very similar on my 1981, and one end of the wire plugs into the junction block, and the other end plugs into a wire that drops down next to the radiator core support.

Re: Brake wire? Need help
 

The wire you have in your hand is the brake warning light, which when grounded will illuminate the light in the dash cluster. It gets grounded if the brake levels in the master cylinder get too low or uneven. It also gets grounded when the ignition switch is turned to the start position for cranking the engine, to test the light bulb in case it gets blown.

The short wire from the master cylinder (proportioning valve) goes to the firewall block, just to the right of the master cylinder, where all the engine bay wires go into the cab.

I believe it is the one on the upper right next to the green wire in the picture.

Attachment 1868078

It then goes into the cab behind the fuse panel and runs over to the key switch.


Attachment 1868077

It is the wire on the right next to the green wires. There are two wires in the picture and the other brown wire goes to the dash cluster plug to terminal 2 next to the pink wire on the plug, and connects to the cluster, which feeds the light. The green wires are not used on gauge type clusters, only on warning light clusters, and they work very similarly. The green wire from the temp sender goes to the firewall block then to the key switch then to the cluster plug to terminal 5.

Attachment 1868079


You may have a problem in the firewall block that requires separating it and re-doing the connection for the brown wire. The end on yours does not look like the right connection for the wires in the block. It could be that someone has installed a different connector on it and routed the wire into the cab to the key switch a different way.

Re: Brake wire? Need help
 

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The connector by your pointy finger is half of a bullet connector. See if the female connector from your old wire will plug into it. I bet it will.

LockDoc

Re: Brake wire? Need help
 

if you cant find the bullet connector or you find one on your firewall harness that reaches to the metering block,
(prop valve for drum brakes) then take off the one you got on your man pointy finger and just plug it in. if its broken altogether from the firewall plug just solder some wire there and solder the other end to the one you have on your hand