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Topic: 3-wire park brake switch (Read 619 times) previous topic - next topic

3-wire park brake switch

My park brake switch has been intermittently working and "partially working", providing a dim park brake light and not turning on the DRL's at some times.  I read the "Parking Brake Sensor Fixed" thread, but found that my switch is different.

It is threaded directly to the valve itself in the dash, and has 3 wires connected to it.  I guess I'll call FT in the morning to order as I have no idea what switch this is and I can't see any markings on it.  When I unplug the connector from the switch, the dash dinger starts going as well, even with the key off.
Keith
2003 U320 38' #6197

Re: 3-wire park brake switch

Reply #1 –
And the story keeps going.  I found the switch on the schematic and it has ground on the center pin and a normally open and normally closed output.  Normally closed sets the park brake light.  Normally open, when grounded, should turn the park brake off and the DRL's on.  While testing with a jumper wire tonight, shorting NC to the center pin (ground), does in fact turn the parking brake light on.  Shorting NO to the center pin dims the parking brake light, but doesn't turn it off completely.  The DRL indicator did come on.  So this tells me the issue is not the switch, but something else in the system.

I have read that the dash gauges are run by a box under the dash and these do go out over time.  Is the parking brake tied into that system?  Could that system be starting to fail and this is the first failure point?
Keith
2003 U320 38' #6197

Re: 3-wire park brake switch

Reply #3 –
That does appear to be the same switch I have.  I don't think the switch is the issue at this point though, as I can jumper from the ground pin (center) of the plug to the normally closed and normally open terminals and get the same effect.

Normally closed, for when the brakes are set, works normally.

Normally open, for when the brakes are released, produces a dimly lit park brake light still.

Keith
2003 U320 38' #6197

Re: 3-wire park brake switch

Reply #4 –
I had a problem that my brake lights are on all the time and no parking lights. I dug deep into harness and next to firewall found a wire that was spliced into brake light with a resistor in it that went to switch for parking lights that was corroded and fell apart.

Re: 3-wire park brake switch

Reply #5 –
For whatever reason, I fired the coach up on Thursday to head out of town and it's all working as it should.  I hate intermittent issues.  Grrr.
Keith
2003 U320 38' #6197

Re: 3-wire park brake switch

Reply #6 –
Quote from: MAZ –
I just replaced mine recently. Might be the same one. Here is where I bought mine.

https://www.onlinecomponents.com/en/honeywell/770400000010001-43482902.html

Mark

I hope that is not the one you have. I wouldn't want my parking brake releasing at 10 psi.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean
 

Re: 3-wire park brake switch

Reply #7 –
Granted, my 1989 GV has way older technology, but I would experience intermittent brake warning light "ON" every once in awhile.
What I discovered that turned the light off was pumping my brake pedal while parking and putting the brake lever on.
Worth a try.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD