I'm long-winded, because I am getting old - please bear with me...

FACTS:

1998 Dodge Ram Quad Cab Largest V-8 Was that a 5.9?, 5.7?

Factory tow package. Steel hardware was replaced because of recall in 2000 or 2001.

I have replaced the trailer socket on the back, under the bumper, twice, since I bought my truck new. The last time I replaced the socket was about three years ago. Until last week, everything worked perfectly, on both trailers.

No one but me has ever done any electrical work on my truck, except to replace the differential, trans, exhaust O2 sensor?, etc.

I have an air compressor (air shocks, and tire filler...) - wired directly into the fuse box under the hood, to a "spare" power blade. The system is otherwise isolated from all other systems. It has been there for 5 years, and a check of the wires and connections shows no significant wear, to any part of it.

I have been pulling two different large trailers for 6 or 7 years, and never had a problem, other than the sockets getting broken, or corroded out. Never have I had any electrical problems when that happened.

Tests at the socket show power to almost everything:

ground
left / right signals
12v aux power
running lights
reverse lights

BUT the brakes, (which share bulb elements with the working turn signals) have no power to either spade in the socket, and the brake controller also has no power at the socket.

Finally, the brakes do not activate the brake controller, but using the switch on the controller itself activates it, in the usual fashion.

~~~~~~~~~~~~~~~~~~~~~~~

I am completely clueless, after several days of poking and prodding with a continuity tester, and a multi-meter. I am beginning to pull out what little hair I have left!

I can not figure out where the brake fuse is, as it is not labeled in either fuse panel. I am guessing that it shares a fuse with something else, but since the turn signals work correctly, it seems apparent to me that either it does not share the turn lights fuse, ~~OR~~ there is a "non-fuse" problem somewhere else.

I am guessing "somewhere else".

I have checked for loose plugs and connections under the dash, as best I can, considering I am far sighted, and need new glasses (times are tough). I have tested the blue brake wire, at the connection point to the socket. No Joy.

My 15 year old, dis-interested in mechanical or electrical stuff (What?...no wireless controller?, no TV?...not interested!) son, has good vision, and if I know just what I am looking for, such as wire or plug colors / sizes / locations / etc., I can have him look for the suggested items, without too much hair-pulling.

I have not chased the problem from the back, to the front, mainly because my vision makes it very difficult to see what I am doing that close up. If that's the only option, I guess I have to figure out some way to get the bottom of the truck at arms length so I can see in detail.

Is there a schematic somewhere on this site? I searched for posts by "weed-someone", but came up empty handed.

Well, that's the long and the short of it. I'm basically stuck at home, until I get this solved, so any suggestions, no matter how unlikely, will be greatly appreciated.

Sorry for the long post - I just wanted try to give all available information right out front, to save unnecessary back and forth postings.

Thank you so very much!

~Blank Stare

 

There is both a trailer fuse and a trailer relay under the hood in the fuse block. As far as a wiring schematic, go to the DIY section and find the link for the FSM. The wiring diagram, and a boatload of other info, is in the FSM. I would post a pic of the fuse and relay but Im on my phone.

 

Go into the FAQ/DIY section and download the free FSM . Have you tried replacing the brake light switch?

 

I found the trailer relay - is there an easy way to test it, short of just buying a new one?

I'll look again for the trailer fuse, but the truck brakes aren't coming on, either...sorry, I may have omitted that detail.

I must be brain-dead...what is, and where do I find the FSM?

Where is the brake light switch - and is it expensive? Money is real tight here, so before I spend more than a few dollars, I'd like to be reasonably sure that will fix the problem.

Thanks for your speedy replies, I REALLY appreciate it.

~ Blank Stare

 

It's mounted on the brake pedal. And cost's around 8 bucks.

 

FSM is Factory Service Manual and it is in the FAQ/DIY section. If you click on the link for your truck it will download the manual for your truck. Lot of great info there.
Ok, back on my computer now and I see there isn't a specific manual for the year 1998. The 96 manual should be sufficient with a few exceptions I think...or maybe the 01 manual would be better. Either way there should only be a few differences. There is also a sticky for parts manuals for all the years so you can download both. Just go to the first page of the FAQ/DIY section and both the service manual and parts manual are stickied there.

 

OK, I must be brain dead. After looking for over 20 minutes, I can not find a DIY, in the FAQ.

I hate to ask, but could you describe where to find it, or perhaps post a link?

Thanks,

~ Blank Stare

 

Link to the thread that has the downloadable service manuals. Hope it helps. There's a wealth of knowledge in there.

https://dodgeforum.com/forum/2nd-gen...e-manuals.html

 

I don't think I would have found that folder by myself - thanks a million!

OK, I have found and read the relevant pages to see how to remove / install the switch. It looks like I have to take the lower part of the dash apart, and maybe the steering column cover?

No big deal, I took the entire dash apart, except for the steering column, when I installed the regulator and gauges for the air system. Not a "fun" process, but at least I already know how.

The burning question, however, is if I can test that switch, once I have it in my hands. Does it work like a regular plunger switch, so that when depressed, it gives continuity? If so, I plan to start disassembling the dash today...

You folks are incredibly helpful. I would still be tinkering with the trailer jack, were it not for this discussion.

~ Blank Stare

 

Thanks for posting this link for him. Was on my phone last night so couldn't post links.