I bought a brake controller to go on my used 95 RAM P/U. The truck has a 7pin RV receptacle for the trailer and all 7 pins are wired. In the cab I see evidence that it once had a controller: mounting holes under the dash and a tap onto the brake pedal switch which goes to +12 VDC when the brake pedal is pushed. How do I trace the controller wire from the receptacle at the rear bumper to the other end so I can install my new controller?
find trailer brake wire
- Thread starter MillWeld
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grsthegreat
Super Star Member
well, im not completely sure about your particular truck, but my 94 dodge ram has a 9 pole female plug up under the dash. the controller had the male end. they simply plug together. id suggest you go ask the parts guy at Dodge..they will have a schematic that they can pull up to show you.
my 2005 ford had the same thing under the dash. I'm guessing that its universal.
If my truck had factory installed towing package there would be a plug under the dash ready to plug into the corresponding cable. That would be the best of all worlds but it is not a factory installed package so as best as i can figure the wire must be traced or install a new one. I'd rather used what is already there.
grsthegreat
Super Star Member
well the thing is....i never ordered my 94 dodge ram with a tow package. i was told that they all come prewired from the factory. i ordered the controller from their parts desk, and they showed me where to plug it in.
did your truck have the rear hitch & 7 wire plug...or did someone add that?
i thought all rams came with that part
also, on the 7 wire rear plug. if you follow the wires back, do they plug into the truck wiring harness?? if so, then the truck had to have been prewired for controller.
sldva00
Silver Member
Most Rams have a female brake control harness (blue) under the driver side dash. You just need to get the male end of the wire harness. If you're getting the prodigy controller, you can get a harness that has the controller hook up on one end and the wire harness hook up on the other.
EDIT:
Sorry, I took too long to post. I see you already know about the plug.
EDIT:
Sorry, I took too long to post. I see you already know about the plug.
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Dmace
Elite Member
Hopefully it's color coded so all you have to do is look for the same color wire, maybe even splice in a new one if you can't find it. It would only take a couple of minutes. You could also unplug the truck battery, connect a 9V battery to the ground and brake controller wires then go to the plug and test the wires one at a time for 9v with a multi-meter.
Every RAM I've owned all came with the trailer brake controller plug under the dash but some didn't have the fuse in the box so there was no power to the charging wire of the 7-pin connector. One 30-amp fuse later and all was good.
I do have the Prodigy P2 and it came with 2 wire harnesses, one for a factory installed package and one generic (requires soldering). I bought it at eTrailer and their videos clearly show the factory installed tow package with the Chrysler Logo stamped on the cover of the 7 pin receptacle. Mine is part of a Reese hitch and has no such logo so someone (dealer?) installed it later. I have scoured under the dash (sore neck) and cannot find a mate to the harness I have. So I think I have to run a new wire 
or trace the existing one. I've seen electricians use devices to trace domestic wiring. Anyone have experience using such for truck wiring?
or trace the existing one. I've seen electricians use devices to trace domestic wiring. Anyone have experience using such for truck wiring?
grsthegreat
Super Star Member
I do have the Prodigy P2 and it came with 2 wire harnesses, one for a factory installed package and one generic (requires soldering). I bought it at eTrailer and their videos clearly show the factory installed tow package with the Chrysler Logo stamped on the cover of the 7 pin receptacle. Mine is part of a Reese hitch and has no such logo so someone (dealer?) installed it later. I have scoured under the dash (sore neck) and cannot find a mate to the harness I have. So I think I have to run a new wire
sure, its called a tick tracer. i have one. they work on any electrical wire. you place one wire of the sending unit on one power wire and the other lead on a ground wire. (the 7 pin receptacle) and the hand held receiver will find the signal source. they have saved my butt many many times. Id probibly unhook the battery to get rid of any signals.
I'm an electrical contractor. you wouldn't believe how many times drywallers have covered up my boxes over the years.
you might be aboe to rent one at a rental yard (ive seen them at our local rental yard)
heres one on ebay
Progressive brand signal tracer set. - eBay (item 160554449345 end time Mar-10-11 17:57:36 PST)
our supply house sell them fo around $50.00 here
Diamondpilot
Super Star Member
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Maybe this will help.
7 way trailer plug wire colors
Dodge Truck brake control install
Its for a 2002/2003 but gives you the basics.
As for just tracing the wires, if there was a controller in it at one time you should see the wiring bundled up somewhere that they ran unless they pulled it all out. Do like Dmace said and put some voltage to it and trace it that way. Just had to do exactly what he said to figure out which cable wire ran to my daughters room. I must have 25 wires coming to a junction in my garage. I just used my jump pack on her bedroom end and then my multi-meter in the garage let me find the right wire in 2 minutes.
Chris
7 way trailer plug wire colors
Dodge Truck brake control install
Its for a 2002/2003 but gives you the basics.
As for just tracing the wires, if there was a controller in it at one time you should see the wiring bundled up somewhere that they ran unless they pulled it all out. Do like Dmace said and put some voltage to it and trace it that way. Just had to do exactly what he said to figure out which cable wire ran to my daughters room. I must have 25 wires coming to a junction in my garage. I just used my jump pack on her bedroom end and then my multi-meter in the garage let me find the right wire in 2 minutes.
Chris
I found it! Thanks for the suggestions - they forced me to look at things again. I had already done the 9v battery trace to no avail. That was because I tested the wrong pins! (dope slap to self). I connected to the pins at 5 and 7 o'clock (bottom two) and came up with nothing, duh!. I had inverted my measurement positions. I changed to pins at 11 and 1 o'clock (top two) and, voila, I had voltage on the blue wire under the hood! Home free.
Thanks, again.
(dope slap to self). I connected to the pins at 5 and 7 o'clock (bottom two) and came up with nothing, duh!. I had inverted my measurement positions. I changed to pins at 11 and 1 o'clock (top two) and, voila, I had voltage on the blue wire under the hood! Home free.Thanks, again.