No turn signals or brakes lights to my trailer

[GShail]

Having turn signals and brake lights is something you take for granted until you do not have them. I felt fortunate to make it home safely after towing a ways without them.



The trailer works when connected to my 06 dually and when connected to anything else, but not in my 03 dually. I figure the problem is in the truck. My plug at the back of the truck was a bit hammered so I replaced it. No luck . . . , still no turn signals or brake lights. I checked the power in the fuse box and all underneath and everything seems ok with just the test light, . . . sort of. On the turn signal wires the test light, lights, but dimly. Read a few posts about the possibility of the need for a reflash to up the amperage, but those posts seem to be tied to 06 and newer. Can't find any posts that mention doing this reflash on anything other than an 06. Can such a reflash be done to my 03, or is it a different kind of system?

 

[Grizzly]

Did you check the fuses under the hood? I believe the 03 has fuses under the dash and under the hood as well. Also check all the light bulbs on the truck.

 

[SDunkle600]

Read a few posts about the possibility of the need for a reflash to up the amperage, but those posts seem to be tied to 06 and newer. Can't find any posts that mention doing this reflash on anything other than an 06. Can such a reflash be done to my 03, or is it a different kind of system?

Yeah on the 06's and up they use what is called a TIPM (totally integrated power module) and no fuses. The reflash is to allow more power to be put to the trailer lights. I believe I read somewhere on here that if you trip the TIPM (like a circuit breaker in your house) you have to go back to the dealer to have them reset it and this can only be done 3 times before it has to be replaced.

 

[GShail]

Yes of course I checked the fuses under the hood and this morning I will go and find my multitester to see what else can be determined. My question is if there can be a reflash done on my truck which is an 03 or is that ONLY FOR 06 AND UP?

 

[GShail]

going to go find my multimeter, I have a sneaking suspiscion that the problem is in the fuse box itself, probably one of those integral/non replaceable relays.

 

[RDyson]

I had the same thing happen on my 03. I pulled the fuses for the turn signals and they were fine. I drug my trailer about 500 miles with only running lights. I checked the service manual and found out that there are a seperate set of fuses for the trailer brake/signal lights. I think they are fuses 46 & 47. They are a 15 amp fuse.



Randy

 

[GShail]

Well after going to it with the multmeter i finally determined the problem to lie in the fuse box itself. Going to install a new one in the morning. I believe that the integral relays that are sealed inside are bad.

 

[PBrauer]

You're jumping ahead... expensively.



Disco the trailer and check the ground at the plug. The trailer sitting on the ball will give you a ground connection but not always a good ground. Your problem is far more likely to be a bad ground at the plug than bad power from the truck, especially since it started affecting two circuits at the same time. The common suspect is ground.



The best way to check it is to measure resistance from the plug to the frame, directly, with a DMM. Too many ways to be fooled by a test light or even measuring pin to pin with a meter or even a plug "tester"... You have "some" current so I'd use a digital vs. an analog meter... easy to miss a few ohms w/analog, which is all it'll take.



You should also plug in the trailer without hitching and check resistance from frame to frame... easy way to make sure the 1st truck vs the 2nd truck wasn't just a coincidence. I'd want to make sure I didn't miss a bad/intermittent ground on the trailer. Manufacturers don't make much effort to ensure the ground on the trailer will last... just a cheap, self tapping screw. I've found bad ones on brand new trailers. No effort to match metals or clean paint. I would expect them all to corrode in time.

 

[jelag]

I'm in the pacific northwest where chemical treatment of the roads goes on all winter long...

I own 3 trucks, all have had the same problem... we have had to remove the factory trailer plug, and hard wire in a new plug and remove the short plug that wires in the factory trailer plug... .

In each case, the road chemicals would work into the connections and damage the wire and the connections... and than any part of this circuit might not work...

We have found that if we use a good uninsulated butt connector and some shrink tubing that has adhesive that melts when shrunk, this style connection is a lifetime repair... we use this same type of connection on any of the light or exterior wiring on all of our trucks... . we also make sure that in the winter when some of the under frame rails collect hundred's of lbs of ice and snow that the wiring is protected so that it can't be damaged...