Stop and Interior 20A fuse keeps blowing

[Mariposa Mike]

Yes I was thinking I would have to remove the door sill plates and rear driver seat if I still have the resistance to check the wires up to the dash. Beyond that I don't see a way to check wires other than the front turn signals before going into the dash. I noticed when removing the front lens one turn signal housing was missing two of the four screws. The ones holding the housing to the fender. So someone has been in there and that could be a clue.

 

[bm02tj]

SEE 19 and 40 check under rear seat

 

[rikkitik]

I recently went through the exact same thing with my Challenger.
I realized that I could break the system into "quadrants" by unplugging the connector feeding each corner circuit.
I then pulled the turnsignal flasher, and determined the "load" (bulb) side. I could then operate the turn signal switch to check side to side.
With the plugs connected, and bulbs in, I had 1.5 ohm left side, .4 ohm right side.
I unplugged the front left TS, and it then read "open" circuit (infinite resistance)......
I went to the rear wiring in the trunk, and found that the plug connector had slid apart slightly. I plugged it all the way in, and "bingo", 1.5 ohm both sides. The front right bulb was the only "load" the circuit was seeing, causing it to draw too much current and blowing the fuse. I'm a bit surprised it didn't blow out the filament.
So, if you can isolate yours the same way, you can narrow it down a bit. First into right/left, then front/rear.
1.5 - 3 ohm good, "open" circuit bad, 0 ohm shorted somewhere.
I hope some of this helps.
Good luck.

 

[Mariposa Mike]

It would really help if I could isolate the problem to one area and this might do it. I have a couple flashers in this car under the dash. I suspect one is for the four way flasher lights. So if I don't find anything with the bulbs out then I can try this method. I do plan to look under the carpet as well and trace what I can w/o tearing the car apart. The more I examine this car the more I believe it was in some kind of accident in the past. To the front. The underside of the hood and the firewalls have overspray and unusual bent metal to the "skeleton" of the hood. One spring has been sprayed the other not. "Curdled" paint on the radiator support and interior lips of the fender where the windshield reservoir is attached. Missing two screws on the passenger side turn signal mounting. Suspect No 1 at this point. Will be looking at those today and thanks for the additional info. When I figure out how to do it I will private message you and one other contributor who lives in the valley area to find out what groups you might belong to for meets. In case I can ever drive this car legally that is.

 

[rikkitik]

You are correct, one flasher for 4-ways, one flasher for turnsignals.
No problem with the "hunt" first, but sectionalizing the system would at least point you in the right direction.
As I mentioned, your ohm-meter will tell you if you're looking for an actual short (path to ground), or something else.
I agree with your weather assignment too.... I'm down in Manteca, with a West facing garage. I haven't been too interested in spending much time in the garage either.
Looks like we have a few days break before it heads back to triple digits.

 

[Mariposa Mike]

Did you disconnect the battery while running your tests? I just finished isolating the front from the dash by disconnecting the 3 bulkhead connectors. I could not get to individual front turn signal connectors due to the hidden headlights and a panel behind the turn signals lights. So I went for the whole enchilada. Reading still the same on the meter. Also disconnected the license plate light but I don't see a disconnect back there to isolate the tail lights. Pulled up the door sill plate but not the protective cover (yet) and no evidence of a screw puncture there. Still need to pull the rear seat up but all the wiring so far is pretty good except for the green corrosion on the body plugs female side and a couple bulbs.

There might be a disconnect from the wiring to the rear if I pull the kick panel but I'm thinking I can reassemble the front lights with bulbs since I have them disconnected. While doing this I'm also looking for a wiring problem with the horns that do not work. I'm thinking it might be the ground wire but it's probably going to be behind the dash as well. And then of course the instrument lights. UGH! But the wipers work

 

[rikkitik]

I didn't disconnect the battery. I pulled the fuses (turn & brake), then tested for the "load side" (bulbs) at the flasher plug in terminals.
One side read "open" (feed/fuse side), the other terminal showed continuity (ohms to ground) when the turn signal switch is activated (right or left).

 

[Mariposa Mike]

I'm probably using a different OHM meter as mine has 200 OHMs as the smallest setting. On that scale I'm reading 30-30.5 OHMs so if that is the open circuit reading then do you have an idea what I should see on a closed circuit? Or maybe I should try to find the meter you are using because mine does not read open. My meter has been good for reading volts and resistance in spark plug wires to determine if those are good but this is my first rodeo on small wiring.

 

[rikkitik]

You can get a decent Fluke multimeter (funny name for an electronics company, but EXCELLENT equipment) for about $50. I would say Klein too, but I have one of their infrared guns and it's inconsistent as hell.
There are a lot of less expensive options too.
But I would consider investing in a "non-automotive" meter. Generally a lot more functionality with a decent multimeter.

 

[Mariposa Mike]

I agree. Fluke and Klein are great meters. I'm using a multi meter that is basically functioning like those but obviously with different scales. Or insufficient scales. My 30 on a 200 scale might be the same as what you were reading on a different scale. I'm cleaning contacts on the front disconnect. Will plug that back in, then clean the bulkhead connectors while I'm there. I removed the rear seat cushion and no wires are under it. I noticed one wire loom going over to the console under the driver seat. But the loom under the metal cover looks great. Don't know what the loom looks like going from the trunk to inside but from what I can see there are no issues there. Still searching..............

 

[kiwigtx]

It would really help if I could isolate the problem to one area and this might do it. I have a couple flashers in this car under the dash. I suspect one is for the four way flasher lights. So if I don't find anything with the bulbs out then I can try this method. I do plan to look under the carpet as well and trace what I can w/o tearing the car apart. The more I examine this car the more I believe it was in some kind of accident in the past. To the front. The underside of the hood and the firewalls have overspray and unusual bent metal to the "skeleton" of the hood. One spring has been sprayed the other not. "Curdled" paint on the radiator support and interior lips of the fender where the windshield reservoir is attached. Missing two screws on the passenger side turn signal mounting. Suspect No 1 at this point. Will be looking at those today and thanks for the additional info. When I figure out how to do it I will private message you and one other contributor who lives in the valley area to find out what groups you might belong to for meets. In case I can ever drive this car legally that is.

Remove the driver's side kick panel and disconnect the 6-way plug going to the rear - maybe another 4 or 3 pin connector there also if there is a console in the car.

Test again and see if the fuse blows. If the fuse is OK now - your problem is in the rear of the car.
If the fuse still blows - the problem is in the front - in the dash area more than likely.

 

[Mariposa Mike]

Thats another good idea. I was planning to remove the kick panel today and do the turn signal tests. I still do not have the bulbs back. When removing the license plate light housing I found the lens has a hole in it. It was obviously hot at one time as the lens is glazed. The hole may have been intentionally put in to drain water. And someone put a couple nuts between the housing mounting plate and the lens. Have no idea why but it made it difficult to remove being crammed in by the bumper. It's now back to original but I have not sealed the hole.

 

[twecomm]

Just don't get too many things going on at the same time. Stick with solving one problem at a time.

 

[Mariposa Mike]

Okay. Maybe some progress but I want to sure I'm thinking correctly. Disconnected the multi wire plug behind the kick panel and checked with the meter on the fuse holder. Now no reading on the meter. NADA. Plugged it back in and shows the 30 again. This with the firewall connectors in place with bulbs in the front turn signals so I thought maybe I would get something on the meter from that when checking the fuse holder. So can we presume that the problem is in the rear harness somewhere? Or the console. And not the dash?

Not sure yet how I will test individual wires. Maybe with a long 14GA wire tied to each wire at the ends until I find an unusual reading. But with so many wires linked together that would maybe only show either tail light or stop light or console or interior, etc. Don't want to proceed until I know I'm on the right track.

 

[Mariposa Mike]

May have found the problem wire. Using non positive terminology in case I'm wrong but tracing wires all day I pulled power wires from the 8 position 7 wire connecter thta is behind the kick panel. No reading on the brown or green wires but when I disconnected the pink wire and checked it with the ohm meter it went to 30 on the OHM meter. That wire goes from the cigar lighter to the connector but I was only checking the wire going back to the center console, trunk lights, interior lights and license plate light. So not sure yet WHERE the issue might be but will start working back on that wire. A schematic I got with the car shows a 6 position connector at the console but I don't see that. The console glove box has pink and yellow and black for ground but the black wires are connected to a green wire that I do not see on the wire chart. And it's very short. Will have to remove the interior of the box to get to the green wire. Then try to find the feed wire for the floor console lights. Interior rear lights last but if the problem is there I might have to just disconnect those. Unless the wire comes from below and is something I can fish. Further to follow.

 

[1 Wild R/T]

If 67 is like 68, and I believe it is the console wiring comes from the drivers door sill and passes under the seat tracks in a channel stamped into the floor... The wires can shift & if that happens they get pinched when the seat is bolted down..

 

[twecomm]

In a 66 Charger, the schematic diagram, fig-3 Body Wiring shows the 8 position connector runs to the trunk. There are only 3 of the 8 wires in this connector involved with tail lamp filaments-license plate lamp and respective turn signal/brake filaments. The gas tank sender (G-4) dark blue is also in this connector, and you should see resistance on that wire measuring respect to ground. If you have the 6 tail lamp and license plate lamp removed at the rear of the car, you should see NO resistance on the following wires in relation to ground. Note: The item in parentheses are wire numbers, NOT connector pin numbers.
Tail Lamps (wire L-7) black wire. R turn signal (wire D-7) brown. L turn signal (wire D-8) dark green.
The pink wire (M-1) in that connector is the for trunk lamp.

 

[Mariposa Mike]

I will connect the meter to those other wires not checked but the method I was using was to remove the wires one at a time and then put the 8 position connector back together and check the load side of the fuse. The pink wire was the first one of the three that gave me the 30 reading again so I figured that was the problem wire. On my wire schematic which is titled 66 Charger supplement shows the pink wire feeding all the interior lighting and the trunk light. The wire chart also shows a 6 position connector that I do not or cannot see at this point. In that connector it shows the pink going from the 8 position to the 6 position in the console. Then to a yellow/pink connector and a black wire going to the truck light. These colors are all like what I see. The interior lights all feed off that pink wire as well and the yellow figures in somehow. Maybe as a return line.

 

[RemCharger]

The 6 pin should be under the seat. ( seat removal)

 

[Mariposa Mike]

10-04. Somehow I was thinking it was going to amount to that. Even to just check the wires as wild rt mentioned. I see where they go under the seat. If I can isolate the problem to AFTER that maybe I can avoid that exercise.