F53 (1994) No brake light or turn signal right side only

[GTodd59]

I am sure this has been covered before, but continuous searching brings me to the same threads that give the overall brake light function but do not cover my specific problem.



As the title reads, my right side brake light and turn signal are out at the rear. Bulbs are good, tail lights work (so ground is good), and brake and signal work on the left side. When I have the right side turn signal on, I get the fast flasher as if the bulb is out. So it would appear that I have no connection to the back from the front.



What I would like to check is the wiring at the front. So my question is, where at the front is the wiring loom that heads towards the back of the bus? I would like to check it where it connects up at the front to see if the wire has anything on it there, as at the back the green wire feeding the right side lights is dead. I should note that I also checked at the trailer wiring connector, and it is dead there too. At the back, the wires go into the bus and disappear after the closet (under the floor I assume) so I can't follow them up and look for a break.



So anybody have a picture of where the rear light harness comes up under the dash?


PS I believe the multifunction switch is a possibility as well. I hope this isn't it because I changed it once already a couple of years back for a different problem. I am not sure where the old one is :(



Thanks

[bobphoenix]

From my previous experience with the F-53 you're right to suspect the main light switch...
When my switch went I had headlights, directional signals, (and four ways) but no clearance lights or rear tail lights...

But, after that, I ran into a problem with the leveling jacks that quit working... That led to an in-depth education of the wiring or that chassis.

There are two terminal blocks on the firewall above your "clutch foot" position, inside the cabin. EVERYTHING terminates (or, originates) from there... this is the F53 "Passenger Compartment Fuse Panel" - main (mine had a second one as well.)

On this panel, fuse number 8 (a 10A Micro2 fuse) controls the power for the trailer light relays... The fact that your turn signals are flashing fast on that side makes me think the relay is not powering up, putting the full load on the flasher, causing it to falsely read a bulb out when there is none... This fuse also controls the Brake lamps feed, Trailer brake control module, Brake on/off signal, and Trailer turn relay coils. (the trailer turn relay receives separate power to light the turn signal lamps, this fuse powers the relay to make sure all the turn signals flash but not too fast with or without a trailer load present...)

Also, and check this first... Fuse number 21 (a 15A Micro-2) controls the Right-hand direction indicator feed. (on the dash...) AND, check Relay 3 on this block... It is the Right-hand direction indicator. (the outside lights...)

The relays are on the bottom of the block and are listed from left to right... (three is in the middle of the five).

Hope this helps...
Cheers, Bob.

[GypsyR]

Before I jumped into the deep end of the pool I personally would use a test light to check out the easily accessible bulb socket itself. I've had more than a couple of bulb sockets give me issues. Focus would be on finding out if the turn/brake feed wire is has power just before going into the socket. Also just because you put a "new" bulb in doesn't necessarily mean that new bulb works or is making proper connection inside the socket. I've been bitten by those issues too.

[GTodd59]

Thanks for the info guys. I hope to have a chance to look at it this weekend to see if there are breakers for the individual sides. I amy resort to hotwiring the right sides to the third brake light just to be slightly safer temporarily.