No power to stop light switch

adileo

adileo

Well-known member
Hi guys

52 F1 all stock - 6 volt pos grd.

I got no power to my brake light switch. I just replaced the switch expecting it went bad but still no good.

All other lights work.

Need path forward. I don’t see any fuses and can’t seem find breaker.
 
Do you have a turn signal switch? If you have turn signals check to see if they are fused. The brake lights operate through the turn switch. The fuse to the turn switch could have blown or the turn switch itself could be bad.
 
Years ago one of the milk trucks at the dairy I worked at had an add on turn signal switch. If the switch lever wasn't perfectly centered between left and right the brake lights wouldn't work. Probably not the problem but you never know.
 
The truck did not have turn signals. I installed a seven wire turn signal switch after market. My turn signals are working.
 
adileo said:
The truck did not have turn signals. I installed a seven wire turn signal switch after market. My turn signals are working.
Click to expand...


Andy .....If, as you say the turn signals are working, and if you have your signal switch wired correctly, you can see that the brake light switch is fed power THROUGH your turn signal switch. I would test the junction where you wired the switch in at point of connection of line #5 to see if you have 6v at that point. Maybe that connection is loose, or worse. If you have no power at that point, there must be a "sneak circuit" or an "open" of some sort INSIDE the signal controller. Check-out this UNIVERSAL diagram. Let us know! DD


L-DIRECTIONAL-TURN-SIGNAL-SWITCH-7-WIRE-ViNTAGE_57.jpg
 
DD

Thanks. Yes I did check that. On mine it’s the orange eire(#5) there was no power to that. I also tried testing that line with pedal depressed. I got nothing. I have a brand new turn signal but was thinking…. Can I provide it with another hot lead? Or should I just put new seven wire in?

Forgive typos sent from phone
 
Last edited:
adileo said:
DD

Thanks. Yes I did check that. On mine it’s the orange eire(#5) there was no power to that. I also tried testing that line with pedal depressed. I got nothing. I have a brand new turn signal but was thinking…. Can I provide it with another hot lead? Or should I just put new seven wire in?

Forgive typos sent from phone
Click to expand...


Electrically, I see no particular reason why you couldn't provide 6v to the #5 wire side of the switch, although your bulb will not BLINK if you have that turn bulb selected, AND the brakes applied. The bulb will stay on SOLID, rather than BLINK. I WOULD disconnect that #5 wire from the MAIN UNIT. You MAY want to throw a cheap fuse holder in that 'NEW' power circuit, as you should understand that the reason for a fuse is to protect WIRING....not that switch.
Personally, I would change-out the entire turn signal switch.
DD
 
Adileo, in my thinking the signal switch doesn't come into play until the brake light switch sends power to it. You said you have no power TO the brake switch. Power to the brake light switch should stay hot all the time. If the feed to the brake switch doesn't check hot, you should find the open circuit or run a new hot wire to the switch.
 
40cpe said:
Adileo, in my thinking the signal switch doesn't come into play until the brake light switch sends power to it. You said you have no power TO the brake switch. Power to the brake light switch should stay hot all the time. If the feed to the brake switch doesn't check hot, you should find the open circuit or run a new hot wire to the switch.
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If you look at the diagram the stop light switch gets its power from the
turn signal switch.
 
Did you check to see if the brake lights ever worked since you installed the turn signals? If they quit working after you installed the turn signals, something got wired incorrectly.
 
tubman said:
Did you check to see if the brake lights ever worked since you installed the turn signals? If they quit working after you installed the turn signals, something got wired incorrectly.
Click to expand...

Denny, everything worked fine for over 3 years.

Bob, before I installed the turn signals. The stop switch was hot.

I’ll do more testing. I’ll find out why or use a new hot lead.
 
Bob C said:
If you look at the diagram the stop light switch gets its power from the
turn signal switch.
Click to expand...

The diagram says the side of the switch opposite the #5 wire goes to the battery. That means it is hot. When the switch is activated the current is routed to the brake lights according to the position of the signal switch.
 
40cpe said:
The diagram says the side of the switch opposite the #5 wire goes to the battery. That means it is hot. When the switch is activated the current is routed to the brake lights according to the position of the signal switch.
Click to expand...
Your right, need to put my glasses on.
 
40cpe said:
Adileo, in my thinking the signal switch doesn't come into play until the brake light switch sends power to it. You said you have no power TO the brake switch. Power to the brake light switch should stay hot all the time. If the feed to the brake switch doesn't check hot, you should find the open circuit or run a new hot wire to the switch.
Click to expand...


40cpe is correct, and I AM FULL of it! I first looked at that circuit and ASSUMED (!!!) that "BATTERY" to the Brake Light Switch was a 'oopsie'. Sure enough, all of these Seven-Wire diagrams show TWO "hot" sources....one to the brake light switch, and a second one to the FLASHER. See below!! DD


d752b87d43f3aabd808766868a8ce238.png
 
If a person doesn't use the OEM connection to the circuit breaker but connects direct to the battery then an inline fuse or the like should be used.
 
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