69 Dart short

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69Dart Custom

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Hello gang,
Guess I was a lil premature when I said everything worked after getting on the road. A shop installed new dash and used the old stock wiring. It turns out I have no running lights and tail lights...and I'm not taking it back to those robbers to fix so I'm taking a run at it myself before I take to another pro. I found the 20A taillight fuse blown. Replaced and blew again. Headlights, break lights, back up lights all ok. I'm planing on checking all the wiring visually next and seeing if I can spot anything obvious. Other than that....and tips or tricks on diagnosis?? Thank you.
 
OK first (if you have not) go to MyMopar.com and download a free factory service manual and then go to the "wiring" section and also download the 2 page aftermarket wiring diagrams. These are not as detailed as the shop manual, but can be easier to follow

Then get into section 8 of the service manual. Just a page or two before the start of the diagrams, is a chart showing what each fuse serves

Once you have that, you can start to troubleshoot. One way is to devise a way to prevent further damage and to avoid using up money by blowing fuses. "Rig" your self at least one stop/ tail light socket/ pigtail and an 1157 lamp. Not an LED replacement, but a lamp. You want something that draws current. "Rig" alligator clips following:

Hook a clip lead to the lap shell, and twist the tail/ stop wires together out of the socket. Hook your second alligator clip to those two. Now hook the two clip jumpers to the two fuse clips. In other words, you have replaced the fuse with this light bulb.

1..Does it light with the light switch turned off? If so, the trouble is likely not in the lighting circuit, but rather something else connected to the fuse shorted

2..The test light will come on with the light switch on. Now you have to eliminate. Start by pulling the connnector loose down in the left side kick panel. This is the harness going to the rear of the car, and carries stop/ turn lamp, tail light, and fuel sender wiring, as well as reverse lamps

If the light is still on "bright" go around front and see if the two front park lights are working--might be "dim". Pull those apart and remove bulbs. At this time, if the short was in the rear harness, and the bulbs removed from front, the test light should be DARK. If it lights, you still have a short "in the car."

A common short area for this problem is where the back seat is near the rear harness, it can "kink" the harness and damage it. Also inspect the rear lights area, the pigtail assemblies in the sockets, etc.
 
Last edited:
67Dart273 said:
OK first (if you have not) go to MyMopar.com and download a free factory service manual and then go to the "wiring" section and also download the 2 page aftermarket wiring diagrams. These are not as detailed as the shop manual, but can be easier to follow

Then get into section 8 of the service manual. Just a page or two before the start of the diagrams, is a chart showing what each fuse serves

Once you have that, you can start to troubleshoot. One way is to devise a way to prevent further damage and to avoid using up money by blowing fuses. "Rig" your self at least one stop/ tail light socket/ pigtail and an 1157 lamp. Not an LED replacement, but a lamp. You want something that draws current. "Rig" alligator clips following:

Hook a clip lead to the lap shell, and twist the tail/ stop wires together out of the socket. Hook your second alligator clip to those two. Now hook the two clip jumpers to the two fuse clips. In other words, you have replaced the fuse with this light bulb.

1..Does it light with the light switch turned off? If so, the trouble is likely not in the lighting circuit, but rather something else connected to the fuse shorted

2..The test light will come on with the light switch on. Now you have to eliminate. Start by pulling the connnector loose down in the left side kick panel. This is the harness going to the rear of the car, and carries stop/ turn lamp, tail light, and fuel sender wiring, as well as reverse lamps

If the light is still on "bright" go around front and see if the two front park lights are working--might be "dim". Pull those apart and remove bulbs. At this time, if the short was in the rear harness, and the bulbs removed from front, the test light should be DARK. If it lights, you still have a short "in the car."

A common short area for this problem is where the back seat is near the rear harness, it can "kink" the harness and damage it. Also inspect the rear lights area, the pigtail assemblies in the sockets, etc.
Click to expand...
 
I just double checked. The tail fuse also serves the lighter, so if the fuse blows with lights off, start there. Access the lighter and pull the wire off the back. it is a push on connector. See if that clears the short.
 
Another trick I use is unplug the connector behind the left kick panel that goes to the back of the car. Replace the fuse if everything is okay the problem is in the rear harness that runs under the back seat to the back of the car. That harness is a lot easier to pull and check then the dash harness
 
That good advice two separate so you know if it's the back or not. Now my dumbass suggestion. Make sure there isn't a penny in the cig. lighter socket.Also make sure tailights have correct bulbs in it.
 
hemi446 said:
Another trick I use is unplug the connector behind the left kick panel that goes to the back of the car. Replace the fuse if everything is okay the problem is in the rear harness that runs under the back seat to the back of the car. That harness is a lot easier to pull and check then the dash harness
Click to expand...

Yeh. I mentioned that. Disconnecting "stuff" is a good way to isolate problems, but you do need to understand "whut" you are disconnecting. Someplace, a guy pulled the bulkhead connector apart containing the ammeter wiring.......and then announced the short disappeared. Of course it did---there was no longer any power!!!
 
Ok gang...d/l the manual, and started as instructed. Had lots of 20A fuses so haven't gone to the auto store yet to rig a light..maybe tomorrow. Did disco the cig lighter, and pulled the plug behind the left kick. Fuse still blows. I'm bettin it's something in the dash install but stay tuned for updates. Thanks again for the assist!
 
Does it blow as soon as you put a fuse in or only with the light switch on? That alone can give you a clue to narrow it down. I would next pull the headlight switch down and inspect it. Might be a short in the dash lamp dimmer. To get the switch out, unhook the battery, reach up around the switch and feel for a spring loaded mechanical release push-button, which I believe is on the top. Pull the switch to "headlights on" push the button and the knob and shaft will come out of the switch as a unit. Then rig a tool to remove the nut from the dash. Be careful not to scratch.

This is a GM switch, but Mopar ones work the same

WiringLiteSwBack2.jpg
 
67Dart273 said:
Does it blow as soon as you put a fuse in or only with the light switch on? That alone can give you a clue to narrow it down. I would next pull the headlight switch down and inspect it. Might be a short in the dash lamp dimmer. To get the switch out, unhook the battery, reach up around the switch and feel for a spring loaded mechanical release push-button, which I believe is on the top. Pull the switch to "headlights on" push the button and the knob and shaft will come out of the switch as a unit. Then rig a tool to remove the nut from the dash. Be careful not to scratch.

This is a GM switch, but Mopar ones work the same

View attachment 1715646667
Click to expand...
 
Doesn't blow until I pull the light switch. I'll pull the unit tomorrow as you suggest. I actually know how to do that from someone on this forum earlier in this build process when I was pullin apart the old dash/gauges.
 
What you might do before you pull the switch is to do a good thorough inspection of the front lighting harness, from each parking light, follow it back all the way to the bulkhead connector, looking for damage, pinched harness, etc.

Since the light switch must be on and since you disconnected the rear harness, there is not much else. The tail lamp power goes down to the kick panel connector you disconnected. The parking lamp power goes to the bulkhead connector, into the engine bay lighting harness, and out to the parking lights.

Also if you have not pull the front lamps apart and inspect the lamps, the pigtails and the sockets and insulators inside the sockets, as well as insulation coming out the rear of them.

The only other thing the park circuit supplies is the dash lamp dimmer. If the front harness does not show up anything, it might be shorted as I said earlier. Start by checking the "INST" fuse which is at one end of the fuse panel. It may be too large. Remove it for testing

The way the dimmer/ dash lamps works is this:

When switch is in "park" or "head" the dimmer rheostat is hot. It feeds "'dimmed" power out on a tan wire TO that INST fuse, and from there to all dimmer controlled dash lamps via orange wiring.
 
Agreed above. I had this issue twice. One was water in front parking lamp from crack in lens. The other was a pinched parking light wire that was pinched under a front fender washer that slid under while I installed the fender. Like said do a visual maybe you'll get lucky.
 
Kendog 170 said:
Agreed above. I had this issue twice. One was water in front parking lamp from crack in lens. The other was a pinched parking light wire that was pinched under a front fender washer that slid under while I installed the fender. Like said do a visual maybe you'll get lucky.
Click to expand...

I have visually chk'd front lamps. Will do more thoroughly as described. As for the dash dimmer....everything there is new and custom. Not sure what the shop did there. But none of the old dash gauge cluster exists anymore. I'll compare your instructions with what I find there. If I had to bet, thats where the issue is. I'm leaving on a mini vacation and will have a week to ponder it before I attack it next week.
 
Back from vacation and back at it. Have made some progress.
Hooked up the test light to the fuse box. Great idea
Pulled the light switch out so I can look at it.
With the left kick harness disco'd, I get dash lights and RF running light.
My left dash blinker light is on.
If I disco the LF running light, the left dash blinker goes out. Neither blows a fuse.
With the LF disco'd and the kick harness reconnected, the test light gets bright(blow fuse) I loose dash lights, the left dash blinker goes on, and the left rear 1157 is on but very very dim.
Pulled seats and traced wires. Don't see anything obvious.
The journey continues.
 
OK first thing is pull apart the LF lamp and inspect carefully.........short (cross) between TS wire and park wire, and "if not" wiggle the heck out of stuff. With bulb installed this WILL show as a short so next step is to pull bulb and see if "short" goes away THEN SEE if the bulb is actually shorted internally or if it works. So jumper bulb "alone" to power source and make sure each filament lights individually to the shell

Next check out rear harness when disconnected. Pull bulbs and inspect as above, and with bulbs removed check for harness shorts and crosses between circuits. with stop lights removed, stop lamps should show individual continuity from one end to other BUT SEPARATE (infinity) to each other (left vs right). and so on.

Sounds like you have two problems
 
By the way did you get a shop manual/ diagram? Go to "MyMopar" and download a service manual, and while there download one of the two-page aftermarket diagrams. These are often not as detailed or complete, but sometimes easier to follow
 
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