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86 R Mack Stop light fuse
- Thread starter shopguy
- Start date
willie59
Administrator
Are you saying the brake light circuit works fine using service brakes, but when you pop the parking brake knob, it turns on brake lights and blows fuse?
2stickbill
Senior Member
Working on a 86 R688 ,keeps blowing stop/turn fuse cant find short, this is one that the park brake turns stop light on but where is that switch?
Thanks for any help.[/QUOTE All the switches I have seen are usually on the firewall behind the steering column.Will be screwed into a block with air lines Most will have two wires and some just one.Wish I had a pic.Find it and check with test light.Some will work with pressure on and some with pressure off.There is usually two one for service and one for park.Unplug wires and you can tell which is which.Hope this garble helps you.
Found a pic.Should be close.Some of the newer ones will be round and sealed.Can not be taken apart.Plus they have blade connectors for the wires.
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well not realy it all works fine most of the time maybe 2 or 3 days then pop no turn sigs,not sure what is doing it yet cant get it to do it in the shop but you got me thinking and it does it on the road not when park is pulled. i just found that the same fuse powers the stop light switch and the flasher , thanks to both of you. Yes Bill it helps because i forgot the pressure off ones.
2stickbill
Senior Member
There is one more thing.I had a 98 CH that the stop lites and turn signal worked thru the turn signal switch on the steering column.Not sure what year does this.Only the ones I had trouble with which was twice one signal wouldn't work.Not sure how you would check this for a short unless wire was rubbed bare and toughed bouncing down the road are turning steering wheel.
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2stickbill
Senior Member
Well glad I was helpful. KW came out with a self cancelling signal switch for a short while.Contacts wore to where one lite didn't work.Took a plastic coffee lid and made a shim.Guy sold the truck said it was still working.I had an air leak a while back under the dash.Thought it was parking valve but it was the same switch your having trouble with.All these new thingamajigs and do dads make if fun to trouble shoot.
I have seen a few.set back axles on a Pete.Rather have the long hood with regular axles
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