77 Supercab Brake Light issue
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From: Auburn,WA
77 Supercab Brake Light issue
I have a 1977 F150 Supercab and for some reason the brake lights dont work (at all), the blinkers work but for some reason one blinks faster than the other (both brand new bulbs), the reverse lights work ok, running lights work ok but hazards dont work either.
We have tried replacing all the bulbs and fuses, tested all the wires and bought a used wiring harness..bought a new Haynes manual...took out all the extra wiring we dont need (towing brake, extra ground wires,aftermarket stuff). We tested the wires for the brake lights (got signal), tested the brake light switch (got signal) and tested the plug (got signal). The only thing that doesnt seem to be working (not sure how to test this thing) is a black box we think is the Directional Switch. Its inside the dash and everything else plugs into it. Only thing, i dont thinks its called the Directional Switch because i've googled/ebay'd ect and only found the actual **** for it. Is this thing called something else???
I cant think of anything else that could possibly be wrong considering we've replaced and tested just about everything. Any ideas how to fix this thing would be great!!!
We have tried replacing all the bulbs and fuses, tested all the wires and bought a used wiring harness..bought a new Haynes manual...took out all the extra wiring we dont need (towing brake, extra ground wires,aftermarket stuff). We tested the wires for the brake lights (got signal), tested the brake light switch (got signal) and tested the plug (got signal). The only thing that doesnt seem to be working (not sure how to test this thing) is a black box we think is the Directional Switch. Its inside the dash and everything else plugs into it. Only thing, i dont thinks its called the Directional Switch because i've googled/ebay'd ect and only found the actual **** for it. Is this thing called something else???
I cant think of anything else that could possibly be wrong considering we've replaced and tested just about everything. Any ideas how to fix this thing would be great!!!
Ford Parts Specialist
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From: Simi Valley, CA
The Turn Signal Switch (TSS) is inside the steering column, not on the firewall. The TSS's wires feed out at the bottom of the column.
A small **** that is connected to the switch protrudes from the steering column's upper flange. Pulling the **** out, operates the 4 way flashers.
Black plastic box on firewall just adjacent to the steering column: Fuse box. There is no **** on it.
Or.....on the far left side of the firewall above the parking brake control: Black plastic Cruise Control Amplifier (if so equipped).
The fuse box cover will have a Ford ID number molded into it, similar to this: D3TB-14A068-AA.
1973/77 F100/350: There are 3 different TSS's. One was used with M/T, one with A/T, one was only used on 1975/77's with Cruise Control.
A small **** that is connected to the switch protrudes from the steering column's upper flange. Pulling the **** out, operates the 4 way flashers.
Black plastic box on firewall just adjacent to the steering column: Fuse box. There is no **** on it.
Or.....on the far left side of the firewall above the parking brake control: Black plastic Cruise Control Amplifier (if so equipped).
The fuse box cover will have a Ford ID number molded into it, similar to this: D3TB-14A068-AA.
1973/77 F100/350: There are 3 different TSS's. One was used with M/T, one with A/T, one was only used on 1975/77's with Cruise Control.
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From: Virginia
Here's the diagram I am using, it may not be totally correct.
AutoZone.com Repair Guide Image
The thing you MUST use to troubleshoot this is a testlight. If you use a voltmeter, you may not figure it out. A testlight puts enough load on the circuits to tell you if you really have enough power to actually run a light, a voltmeter will not.
Put the turnsignal switch in the center position. Use the testlight and while pushing on the brake pedal, see if you have voltage on the red/black coming from the brakelight switch, going into the turnsignal switch. If you do, then check the green wire leaving the switch, and also the yellow/black wire. Both these wires go to the rear lights. If you do not have voltage on these wires while pushing on the brake pedal, but you had it coming into the switch on the red/black, then the turnsignal switch is bad.
AutoZone.com Repair Guide Image
The thing you MUST use to troubleshoot this is a testlight. If you use a voltmeter, you may not figure it out. A testlight puts enough load on the circuits to tell you if you really have enough power to actually run a light, a voltmeter will not.
Put the turnsignal switch in the center position. Use the testlight and while pushing on the brake pedal, see if you have voltage on the red/black coming from the brakelight switch, going into the turnsignal switch. If you do, then check the green wire leaving the switch, and also the yellow/black wire. Both these wires go to the rear lights. If you do not have voltage on these wires while pushing on the brake pedal, but you had it coming into the switch on the red/black, then the turnsignal switch is bad.
Thread Starter
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New User
Joined: Sep 2009
Posts: 19
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From: Auburn,WA
The Turn Signal Switch (TSS) is inside the steering column, not on the firewall. The TSS's wires feed out at the bottom of the column.
A small **** that is connected to the switch protrudes from the steering column's upper flange. Pulling the **** out, operates the 4 way flashers.
Black plastic box on firewall just adjacent to the steering column: Fuse box. There is no **** on it.
Or.....on the far left side of the firewall above the parking brake control: Black plastic Cruise Control Amplifier (if so equipped).
The fuse box cover will have a Ford ID number molded into it, similar to this: D3TB-14A068-AA.
1973/77 F100/350: There are 3 different TSS's. One was used with M/T, one with A/T, one was only used on 1975/77's with Cruise Control.
A small **** that is connected to the switch protrudes from the steering column's upper flange. Pulling the **** out, operates the 4 way flashers.
Black plastic box on firewall just adjacent to the steering column: Fuse box. There is no **** on it.
Or.....on the far left side of the firewall above the parking brake control: Black plastic Cruise Control Amplifier (if so equipped).
The fuse box cover will have a Ford ID number molded into it, similar to this: D3TB-14A068-AA.
1973/77 F100/350: There are 3 different TSS's. One was used with M/T, one with A/T, one was only used on 1975/77's with Cruise Control.
Thread Starter
|
New User
Joined: Sep 2009
Posts: 19
Likes: 0
From: Auburn,WA
Here's the diagram I am using, it may not be totally correct.
AutoZone.com Repair Guide Image
The thing you MUST use to troubleshoot this is a testlight. If you use a voltmeter, you may not figure it out. A testlight puts enough load on the circuits to tell you if you really have enough power to actually run a light, a voltmeter will not.
Put the turnsignal switch in the center position. Use the testlight and while pushing on the brake pedal, see if you have voltage on the red/black coming from the brakelight switch, going into the turnsignal switch. If you do, then check the green wire leaving the switch, and also the yellow/black wire. Both these wires go to the rear lights. If you do not have voltage on these wires while pushing on the brake pedal, but you had it coming into the switch on the red/black, then the turnsignal switch is bad.
AutoZone.com Repair Guide Image
The thing you MUST use to troubleshoot this is a testlight. If you use a voltmeter, you may not figure it out. A testlight puts enough load on the circuits to tell you if you really have enough power to actually run a light, a voltmeter will not.
Put the turnsignal switch in the center position. Use the testlight and while pushing on the brake pedal, see if you have voltage on the red/black coming from the brakelight switch, going into the turnsignal switch. If you do, then check the green wire leaving the switch, and also the yellow/black wire. Both these wires go to the rear lights. If you do not have voltage on these wires while pushing on the brake pedal, but you had it coming into the switch on the red/black, then the turnsignal switch is bad.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 785
From: Simi Valley, CA
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its supposed to but it doesnt work
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From: Auburn,WA
no its not, i have traced BOTH wiring harness' and compared them to the diagram and this is what it all goes to
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