Tow Light Relay? YGTBSM!!!

[Adventure Bob]

Ok having read this and some other forums it would appear that DC in their infinite wisdom put the L/R trailer brake and blinker relay on the main circuit board of the PDC as opposed to actual user changeable relays. Anyone else run into this? Evidence is one side or the other not working for brake/blinker. I'm simply amazed that the DC recomended fix is a new $800 (part only) PDC. Anyone mod this stupid thing to get real relays working?



Any help or suggestion appreciated.

 

[jelag]

The tail lights and brake lights on the truck are on different circuits and fuses than the lights/wires in the trailer plug... so that if you blow the circuit in the trailer harness the truck lights still work...

You don't say which truck you have but here have been some overloads associated with some of the newer trucks and the dealer has to reset and reprogram the trailer harness circuits for higher amperage... . normally this has been done under warranty as I recall there is a TSB on this... .

On all our trailers we've installed an 8 gauge wire to charge the batteries with the same size ground and than have a set of relays in the trailer that draw current from the 8 gauge 50 amp circuit to power lights... we just use the power in the trailer harness to control the relays and run the brakes... so we've run a separate wire from the batteries through a 50 amp breaker to the rear of the truck...

On our heavy trailers we've found that our batteries are at a higher rate of charge and the lights are no longer dim at the rear of the trailer...

Does this help...

 

[DE Jeeper]

If you do a search someone on the board posted pics with directions on soldering on pigtails for external relays. I may do this eventually, but in the mean time I just tapped into my rear light harness. I dont draw enough on my trailer lights to blow the fuse. I am currently having a problem with the brake light on that same side now, but I am unsure if it is related because I just pulled it out of its winter storage and the problem might be with the trailer.



Aaro

 

[ryecreek]

10 amp fuses fix this rather than 15 amps(from dc) space 46/47 i belive

if ya got a dead side and the fuses are good its roasted in the pdc no real fix. beleive 03 and 04 were the worst i did a temp patch with a universal trailer wiring kit and a relay but i may fry other things. (just search my posts)

contact Twest and he'll help thats where i got my new pdc

 

[EricBu12]

Lucky I have all LED Lights on my 5th wheel 'cept for the 2 mid trailer Turn signals.

 

[steved]

10 amp fuses fix this rather than 15 amps(from dc) space 46/47 i belive

This only applies to the older trucks that use a fused circuit to protect the circuits... the newer trucks use the computer to protect the circuit.

Lucky I have all LED Lights on my 5th wheel 'cept for the 2 mid trailer Turn signals.

Which means nothing if you happen to develop a direct short in the wiring... a short is a short.

 

[Adventure Bob]

I'm in an 03, and if you have the tow pkg those relays are not changeable by the owner. DE Jeeper, do you have the same prob?

Jelag, I can run a seperate set of wires, not the issue, I'm just confounded at the stupidity that would allow an EE to think a relay soldered to a circuit board that was not changeable by the user was a good idea. Or maybe that was the plan: planned obsolescence. Keeps dealers in work I guess.

 

[steved]

Since you have an 03, I would definitely drop the amperage of the fuse used in those circuits as was previously stated. I dropped all of mine by half, and used either 7. 5 amp or 5 amp fuses... but I only tow smaller trailers with LED or very few bulbs.

 

[d6c]

2006 and newer (iirc) really need a stand-alone fuse block to protect the non-servicable factory trailer circuits. I know you could do this at the plug-in behind the back bumper,but it would be cleaner and more servicable if it was underhood. Painless Performance comes to mind and I'm sure they have the techs to science out a really nice product. If owners knew how delicate and expensive to r/r the factory components they would be hesitant to plug in to any old trailer!

 

[rbattelle]

If it were me, I think I'd pull the IPM and replace the relay. Has anyone tried this?

Ryan

 

[steved]

There was a complete writeup in the towing section on how to replace the relay, not something easily done by most as they are soldered onto the board.

 

[Adventure Bob]

Could someone throw a brother a hand and post the link to the refd article? Ive searched every combo of words I can think of but cant find that write up...

Thx

 

[steved]

It was in the towing section, I'll look later this AM.

 

[steved]

https://www.turbodieselregister.com.../205699-lost-left-turn-signal-7-way-04-a.html





Might try PMing this guy, he actually has done it...

 

[Adventure Bob]

Thanks Steved, not quite the tech article I was hoping for but htanks for looking.

 

[ryecreek]

https://www.turbodieselregister.com...smission-discussions/214406-05-part-03-a.html



https://www.turbodieselregister.com...s/216352-factory-trailer-wiring-question.html

try those if not look through my posts

PICs must be gone but they show the citcuit fried(burned and broke) not the relay