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lighting and electrical woes

lighting and electrical woes

Helomedic1171

Jeeper
Posts
149
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Location
Savannah
Vehicle(s)
'85 CJ7 258, T-176, D300
'58 CJ5 F4-134, T-90, Spicer 18
'54 M38A1 F4-134, T-90, D18 (28VDC and milspec parts)
Alright folks, been a long-time lurker and watcher here, trying to sponge up all that I could. here's my problem - I'm working on the 85 CJ7 in my sidebar. I've been replacing and tracing and checking and rechecking all sorts of things, and today, I finally got the reverse lights, brake lights, and turn signals working. Headlights already work, next is the dimmer.

Problem: after I traced the reverse lights down and found a loose connection in the 4-wire weather-pack (is that what jeep guys call it, or is that a GM term?) on the firewall, and the brake lights stopped working. they worked before that. I had just finished the stoplight switch, brake lights worked beautifully, as did both rear turn signals. Now, I lost brake lights and the rear turn signals. Reverse lights still work, subject to the whims of that loose weather-pack, running lights, and front turn signals are all working.

this is driving me nuts, but I kind of expect it since, you know, this IS a Jeep. Next week - what in unholy fork are all of these random wires under my dash that A. aren't hooked to anything and B. have 12VDC during KEEO or in some cases, at all times.
 
Often times these kind of problems are due to a bad ground. I test by running a wire from the negative side of the battery and touching it to the ground for what ever is not working is supposed to be.
 
Thanks. Any ides on what/where some common culprits are? this CJ7 had some serious rust issues due to salt or saltwater, not sure which. Amazingly, the frame is in GREAT shape, so I think this thing lived near the beaches down here in coastal GA for along time, but who really knows.

The Tail lights are grounded by the metal plate in the housing, and the starwashers/screws that hold them on. what other commonly failed grounds should I check, and where do I find them? also, would it be smart to upgrade the battery cables to a bigger gauge, and replace the frame-to-block and block-to-body grounds? I'm assuming jeeps have these, but maybe not - my Jeep knowledge is small and I may be confusing these with a Transmission Am or a truck.
 
Brake light and turn sigs are routed through the turn signal switch.
Jeep CJ's and GND issues are sadly, common.
I hard wired a GND lead from my dash panel to the battery NEG many years ago and that got rid of many issues.
Also hard wired a GND form the gill to the fenders and to the firewall.
Make sure your frame is grounded to the body and the engine.
LG
 
Cool. I'll try those fixes. Come to think of it, my dash isn't really attached since I'm working on electrical and lighting. I'll add a ground strap in this spots you just point out, and also check my frame-body-block connections. I think I'm going to grab some bigger battery leads too. I'll post up with results.
 
Forgot to mention, I also found in the FSM where the major grounds are located, so I'll check those out also.
 
What we ended up doing was running a heavier ground wire directly from the battery to a ground block that we located under the dash. We then ran separate ground wires from the ground block to each device. No more ground problems since rusty metal is now completely out of the equation. We plan to do this on the other Jeeps we have that are still in the works.
 
Any way you could post a picture of the block? Or did you use like a junction block with screw terminals?
 
Z2zypufo5oy.webp

Lots of different styles to choose from. Some are covered, some are round, this is what we used since we mounted it under the dash away from the weather.
 
I have 'buss-bar' on the engine side of the firewall.
Very handy.;)
LG
 
87cdb8919241a22e36f6a61dac7fe3bf.jpg


Here is the one I installed to solve a lot of my interior grounding issues. Love it.
 
Be cautious about those plastic covers. They 'trap' and hold condensation.
LG
 
getting ready to order some terminals, lugs, and others stuff. I have the cable and heat shrink, but I need better terminals to do this right. Also, anybody have an idea where to get a set of crimpers for 2/0 cable that are affordable? (less than $100) trying not to spend $250 for a set of crimpers I'll only use here and there.
 
no kidding? wasn't sure, but 30 years is a good track record. thanks! do you solder your connections too? I kept thinking about using this one since the mechanical connection would be bolstered by the chemical connection of soldering the connection. Also, a regular soldering iron (30 watt?) isn't going to cut it with a 2/0 cable, should I use a torch or one of those 300 watt soldering guns?
 
Yes-I crimp then solder whenever possible.
I use 60/40 (lead/tin)rosin core solder only.
On heavy cable 0/0 and above. I use a handheld LPG torch.
300W solder iron takes to long to heat the area and won't heat the area evenly.
Use external star-washers when ever attaching terminals to sheet metal, engine block etc. for better contact.
Coat with battery terminal anti-corrosion spray when done.
Good luck,
LG
 
Not to over-do this thread, but it's "almost" best just to pretend you have a fiberglass body and just manually ground whatever whenever and wherever you can.

I've wasted more time than I'll ever admit on issues that were ended up being either bad grounds or junk battery cables - even new ones.
 
I'm starting to get that idea reading the 85 pages or so of Jeephammer preaching the gospel of proper automotive electrical wiring. I ordered some battery terminals and lugs, and I'm about to order a pack con set and some packard 56 and 59 terminals and a tool for them all. I picked up a 10-terminal bus bar yesterday and some brass bolts and nuts so I can make a whole new set of grounds. I'm going to make all new grounds and then re-evaluate how things are working. I just feel like I'm chasing my tail with some of these wiring issues, so why not fix the grounds for good (or at least a really long dang time) and then see how it's going? after all, once I do the MPFI swap, I'm going to need better grounding and good electrical for it to work right. thanks for the help so far guys, I have finals next week, so it'll be a few days at least before I report back.
 

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