Installing trailer wiring

[wrk2mtch]

I am installing a 7-pin plug and I'm wondering where the best place is to tap power to switch a relay is. I see that there is a 2-pin connector and a 3 or 4 pin connector under the dash that are not connected to anything. Does anyone know what these are for? Is one of them for a brake controller?
Thanks in advance.

------------------
'90 LE W250, 727, 3. 07, Line-X bedliner, 140k miles,

 

[Wirenut]

Nice post Terry. For me... same question about the brake controller. I just bought a 28' 5th wheeler yesterday.

------------------

• '93 250 LE 4x4 5spd 4:10 Loaded,dual 5" chrome stacks,12cm² turbo(37psi),PW injectors,K&N,pyro/boost,US Gear E-Brake,tool box,CB,10" AR rims, 285/75/16 Bf goodrich. "wirenut_21529" on Yahoo Messenger
• '97 Ford B-Series school bus (5. 9 Cummins!)I'm gonna Bomb it!
• '94 GMC 2500 6. 5L Turbo

PICTURES.

 

[GeneH]

The 4 wire black connector is for the factory tach(no longer available).
Black wire is ground
orange wire is instrument panel light dimer
gray wire is the signal from the computer for the tach.
red wire is ignition switch 5 volts
Gene
92 350 4x4

[This message has been edited by GeneH (edited 05-20-2001). ]

 

[M'staedt]

Hey Gene,
I see a lot of threads regarding tach wiring. Is this connector on all 1st gen. trucks? Will any aftermarket tach plug into it or is the factory tach a special, diesel only model? Do you have any idea what the signal frequency is from the connector?

Thanks... Mark

------------------
Love them old Mopars
('69 Charger R/T and '78 Li'l Red Express Truck)

 

[wrk2mtch]

Unfortunatly, the relay I bought grounds through the housing so I need to find a 12v switched lead for the it. Does anyone know what the other plug under the dash is? It's right at the bottom and it has 2 wires.

------------------
'90 LE W250, 727, 3. 07, Line-X bedliner, 140k miles,

 

[CrewCabDiesel]

Terry, what are you using the relay to power and can it be located under the hood? Also what is the relay rated at for trigger voltage/amps.
Kyle

 

[wrk2mtch]

I installed it under the hood yesterday. I'm not sure what the trigger voltage/amps rating is. I am using it to isolate the truck battery from the trailer batteries (I learned that lesson already!). I was planning on running the 12v lead for the brake controller off of the truck battery side of the relay but I thought that while I'm running the wiring for the brake controller through the firewall I can run a switched wire to the relay too.

------------------
'90 LE W250, 727, 3. 07, Line-X bedliner, 140k miles,

 

[GeneH]

M'staedt,I believe all the 1st gen's are wire for the tach, atleast the mopar catalog list two different pn's one for 89-91 and 92-93. I don't know the signal freq. or if other after market tachs will work off the tach signal from the computer. Do a search with tach as subject, this has been discussed before.
Terry H. the other two wire connector is for the dealer to plug into to check the RWAL brake system.
Gene
92 350 4x4

 

[CrewCabDiesel]

Trailer brake wiring doesn't use power from the dash except for the tapping into the brake switch(or at least the one I use, Draw Tite 4 axle brake controler). I just followed the directions from draw tite and it works fine. I did run an extra 12 gauge ground wire from the battery, most Chrysler products I have worked on tend to be weak in having good ground connections. As far as I know, 1st gens didn't have a built in brake controler wiring. Also factory tachs wiring I believe started in 1991. 5 models with the addition of a computer behind the battery.
If you want to switch a relay under the hood, use the ground circuit and that way you only have to run 1 wire through the fire wall, and its not powered so you lower the risk of a fire due to shorting. I run all my outside accessories that way like fog lights. If you like I can describe the trailer wiring on my truck.
Kyle

------------------
1985 DODGE 1 ton Crew Cab W/8' box converted to 4X4 in 1999. Upgraged to a non-intercooled 1991 Cummins Turbo diesel & rebuilt 5 speed Getrag in January 2001. Freshly rebuilt and Balanced Cummins, Rebuilt NP205, Rebuilt Injector pump and tweaked, Matched Injectors, 3" New Mandrel Bent Exhaust,no muffler, Borgeson Steering Shaft, K&N Air Filter, 3:54 gears, limited slip rear end, 16" Goodyear GSA Wranglers, 16K Reese 5th Wheel Hitch,and LE Package, OEM Cruise Control, All New R134A AC, and a Sony CD Stereo. If you want to know why I did all of this, 3 kids and I can't stand F**d and Ch**y. Kyle Hoover ,Fruitport, MI.

 

[Case500D]

When I installed my Voyager brake controller, I did the following:
1. Bought a "wiring loom" (10 guage wire in a heavy, flexible plastic conduit) and ran the hot wire to the + battery terminal and the ground to the - side of the battery. This is what the instructions stated to do for the best performance.
2. I also installed a 30 amp circuit breaker on the driver's side fender just behind the battery. This was also recommended by the instructions.
3. I "hard wired", or soldered and heat shrinked every conection. That way I only have to do it once.
4. I also ran the hot and ground wires to the rear using the left frame rail. I zip strapped everything down so nothing would be rubbing.
5. Make sure to put a rubber boot over the backside of the plug (where the wires go in) or it will be full of dirt and salt in no time. Some even recommend filling this with silicon grease to help prevent corrosion. I didn't because I didn't have any at the time.
6. Tapping into the trailer light wires was very simple, if you need the color codes let me know.
I am glad I did it this way because I have had no problems in two years. Hope this information can help someone out.

------------------
Jeremy Sweeten 1992 Dodge W-250 4x4 Cummins Diesel, Intercooled,LE Package, 168K, 518 AT, Warner Hubs, Dana 60HD 4,060 lb. front axle and Dana 70 6,084 lb. limited slip rear axle with 3. 54 gears, NPG 205 transfer case, 3. 5" Banks exhaust straight pipe, K&N air filter. 3" rear brakes with 1-1/8" wheel cylinders. Tekonsha Voyager XP electric brake controller. Una-Goose 30,000 lb. gooseneck hitch.
http://home.earthlink.net/~sweeten1/index.htm

 

[wrk2mtch]

Thanks CASE500D.
Did you switch the hot lead for the trailer, or did you run it straight to the battery?

------------------
'90 LE W250, 727, 3. 07, Line-X bedliner, 140k miles,

[This message has been edited by Terry H (edited 05-25-2001). ]