Click on image for the lowdown. 
====
| | | Forums66 Topics128,147 Posts1,056,798 Members48,454 | | Most Online14,466
Apr 26th, 2026 | | AD Chevy Trucks  Over 6,000 pictures Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips. Check them out!
Lots of work on Brad's part ... pure enjoyment (and references) for you!
| | THANKS!
For helping keep this great
old truck web site
on the Internet for over 30 years! and not clogged down
with Ads!  Again, thanks!
| | | | Joined: Jan 2012 Posts: 33 New Guy | | New Guy Joined: Jan 2012 Posts: 33 | Mystery Box So this box with a knob that slides horizontally is hooked up under the dash. I have no clue what it is and what it is supposed to do. My google searches are too general to come up with any results. Any guesses?
'64 C10 1/2 ton fleetside
| | | | | Joined: Dec 2001 Posts: 14,522 Moderator: Welcome Centre, Southern Bolters, Legion Hall | | Moderator: Welcome Centre, Southern Bolters, Legion Hall Joined: Dec 2001 Posts: 14,522 | something to do with pulling a trailer???? ...my GUESS. | | | | | Joined: Mar 2011 Posts: 457 Shop Shark | | Shop Shark Joined: Mar 2011 Posts: 457 | Yes, looks like a controller for electric trailer brakes. Should have a bunch of wires attached.
1940 Chevy 1/2 ton pickup "KC"
A day without sunshine is like, well, ..... dark!
| | | | | Joined: Dec 2005 Posts: 2,557 'Bolter | | 'Bolter Joined: Dec 2005 Posts: 2,557 | Electric brake control box.I had one on a 1966 3/4 ton truck just like that one.I want to say it had a copper line that ran to a T in the master cylinder brake line.I don't think it had very many wires to it,but I can't remember.
Tim
1951 3100 Chevrolet1951 Chevrolet Suburban CarryallImage"A house is built with boards and beams. A home is built with love and dreams." "Look deep before you leap !!!" / "Everything is Everything" "If I say a mouse can pull a house, hitch him up"
| | | | | Joined: Jan 2008 Posts: 4,962 'Bolter | | 'Bolter Joined: Jan 2008 Posts: 4,962 | Its a Kelsey Hayes brake controller. Electronic ones are still being made. http://www.hayesbc.com/ | | | | | Joined: Feb 2004 Posts: 29,846 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,846 | That's the older design trailer brake controller that incorporates a hydraulic connection to the master cylinder. It will have a power wire connected to battery voltage, an output line going to the trailer brakes, and a smaller-gauge third wire connected to the brake lights. It works with either hydraulic pressure from the brakes, or manually by moving the handle side to side. The knob turns to adjust the sensitivity, so the output to the trailer can be reduced when running unloaded to avoid locking up the trailer brakes. Later model electronic controls don't have the hydraulic connection because it interferes with anti-lock brake systems.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!
| | | | | Joined: Nov 2011 Posts: 139 Shop Shark | | Shop Shark Joined: Nov 2011 Posts: 139 | Have had several trucks and vans with trailer brake controllers. Would have to agree with everyone else that's what you've got. | | | | | Joined: Sep 2010 Posts: 698 Shop Shark | | Shop Shark Joined: Sep 2010 Posts: 698 | I had that exact same model electric brake controller on my '73 C10.
Boy, that brought back some pleasant memories.........
My Fleet: 19411953195919651966 1953 Willy's Pickup John Vegetarian- old Indian word for bad hunter
| | | | | Joined: Feb 2002 Posts: 2,893 Socket Breaker | | Socket Breaker Joined: Feb 2002 Posts: 2,893 | electric trailer brake It looks exactly like the one that was on my '65 c10 when I bought it. I left it on there until it started leaking brake fluid from the box itself. the one I used to have If everything is still there, a big honking 6 or 7 prong plug box should be on the back somewhere. -W | | | | | Joined: Feb 2009 Posts: 400 'Bolter | | 'Bolter Joined: Feb 2009 Posts: 400 | and when you push on the brake pedal the knob would move. | | |
|
|
