Parking Brake Switch Instructions

[Tinwoodsman]

Does anyone have a picture or instructions on the installation of the parking brake switch normally found on the A3 but workable on the A2?

 

[steelandcanvas]

No instructions, but would a photo or two and some wire numbers help you?

 

[Tinwoodsman]

Absolutely, thanks.

 

[AceHigh]

While you are waiting a short summary. You get the 24 volts positive, then to the light, then to the switch and finally to ground.

 

[steelandcanvas]

The wire numbers are #16 & #127. I hope you can make something out of the photos. One shot was obviously taken straight down, and the other was taken from the back corner of the cab. Hope this helps!

 

[clinto]

It's the one with the switch mounted in the rear of the parking brake handle (same as the late model USAF M35A2C's)?

 

[doghead]

Does the light help keep you from driving off, with the parking brake on?

We all know that happens!

 

[1 Patriot-of-many]

I've found it doesn't matter if the light works or not, if my parking brake is on, you know it. If the opposite were true there's no need for a light anyway.....

 

[Tinwoodsman]

Thanks S&C. It is the mounting of the switch assy on the parking brake handle that I wanted to check on. Appreciate it and the comments from the rest of you.

 

[steelandcanvas]

Thanks S&C. It is the mounting of the switch assy on the parking brake handle that I wanted to check on. Appreciate it and the comments from the rest of you.

Are the photos OK? Did they show enough of the the mounting to help you out? If you need some more views, just say the word! Glad to have helped!

 

[Tinwoodsman]

My switch is on the way from Saturn so I will let you know if I need anything else. Thanks again.

 

[rrrr]

This is a great mod. I hate when you get that awful smell in the cab and the oh crap feeling when you realize what it is.

 

[Tinwoodsman]

It think I will wire it to a dash fan to blow air in my face if the brake is on.

 

[steelandcanvas]

It think I will wire it to a dash fan to blow air in my face if the brake is on.

How did that work out for you Tin? My light on the dash stays on now, even with brake released. I disconnected the ground going to the switch with the parking brake off and the light went off....hmmm, bad switch. I connected a few wires that had came loose under the dash incorrectly, and welded the contacts in the switch. That switch has to be cheaper than the dash indicator light ($35). I really got used to the brake light indicator, beats the smell of burnt brake linings.

 

[Tinwoodsman]

Steel,

I deep sixed the fan idea but did get the switch and dash light installed. Worked great but I do miss the burnt brake drum smell....

 

[WWIILBird]

Installed the parking brake switch and light today on my M35a2, I really like having the light reminder but I have one issue. When the parking brake handle is down the light comes on and when the brake handle is pulled up the light goes out. It seems the switch can only go on one way. I took power off a switched lead (#27) and connected it to #27 on the light then ran a wire from the light (#67 (-) to the switch. Then I connected the ground wire from the switch to a bolt for the parking brake mount.Seems simple enough so what did I do wrong? Looked at the wiring diagram. The route I took is similar to the wire diagram except #67 is connected to #118 which then connects to switch. Thanks.

 

[doghead]

Here's the switch on the A3 schematic.

 

[steelandcanvas]

Installed the switch and light today, I really like having the light but I have one issue. When the brake handle is down the light comes on and when the brake is pull up the light goes out. Can someone tell me how to correct this? It seems the switch can only go on one way. I took power off a switched lead and connected it to #27 on the switch and ran a wire from #67 (-) to the switch. Seems simple enough so what did I do wrong? Thanks.

The positive doesn't even go to the switch. The positive goes directly to the Brake Indicator Lamp. Run a wire from the negative side of the Indicator Lamp to one side of the switch. Run a grounded wire to the other side of the switch. You are turning the Indicator Lamp on and off by switching the negative, not the positive. I don't know why you don't have a dead short through the switch.

 

[WWIILBird]

I edited my post, it wasn't accurately describing what I had done.

 

[WWIILBird]

Some pictures of installation