Mariposa Mike
Well-Known Member
440-4spd. I used a better light and my reading glasses and do see the four screws on each side. That makes sense now.
Stop and Interior 20A fuse keeps blowing
- Thread starter Mariposa Mike
- Start date
OneOfMany
Member
Had similar problem on a demon years ago. It was actually one of the taillight bulb sockets. Looking in after removing the bulb, the plastic at the base had melted causing the short. All external wiring was fine.
Is the fuse element actually blowing or is the end in the cap melting..
2 different problems with the same outcome.
2 different problems with the same outcome.
OneOfMany
Member
On mine, fuse blew every time I hit the brake pedal
Mariposa Mike
Well-Known Member
The fuse is blowing. And the lights and stop lights will work for a brief time. The only clue I have on them not working is the interior lights no longer glow. I will check the bulb difference as I now have both numbers to see if there is a difference in the pins.
Mariposa Mike
Well-Known Member
Just one added note. This car has the four way flashers. I read a note that those were dealer installed. Not sure how those fit into the wire harness yet but maybe that has an issue affecting the rest. Seems like it would be in the same wiring loop.
Something else to be aware of is that these dual filament bulbs as used in the tail lights / stop lights have stepped height side pins. The small pins of the bayonet base on the on the sides of bulb and the sockets are at different heights. This is so the bulb get oriented properly unto the socket. The 1157 lamp has a slightly higher current draw on the bright filament but not enough to cause your problems.
Did you do the check with ohm meter and no lamps installed for shorts ?
Did you do the check with ohm meter and no lamps installed for shorts ?
Last edited:
Mariposa Mike
Well-Known Member
Have not checked it yet but I'm close. We have been going thru a terrible heat wave here. Working outside or in the shop only lasts a couple hours after chores. Besides that I'm selling my Jeep LJ and the fellow was coming next week but now he is coming this week (today) from afar and he and his wife will be staying over. It's someone I know. I needed to clean it out, gather all the papers and service info. and do a anti freeze service. Today I had a 9 AM appt with the CHP to do the VIN verification on the Charger and that was done. But it's 107 degrees out and I ain't goin' back out there. I know. Sounds like excuses but I can't get back to this until Sunday. Supposed to start cooling down some here thank you but the heat is moving east so watch out.
Got my 10 pack of 1034 bulbs though and the main difference I see is the 1157 are a brass base with recessed contacts and the 1034 are bright metal with protruding contacts. Same as the ones in the car. The contacts on the car bulb socket wires are also protruding. The bulb pins look the same on both. I was trying this morning to find a metal brush to ream/clean out the socket although these look pretty good. Did not find anything to use but may hit them with some emery cloth. I'm not suspecting a short there but after all these years just want there to be a good contact and ground. Was also thinking of dismantling the lenses to get a better look at the wires where they lie on the inside of that housing. Process of elimination going forward in the car. As soon as I check with the OHM meter, assuming I do it correctly I will post the results. If it reads okay then I might have to go to another switch in the system. Like the brake light switch. There is an extra one with the spare parts so that might be the original. Just don't know what was done before. Like ONEOFMANY said his blew every time he hit the pedal. That was in play when these went out.
Got my 10 pack of 1034 bulbs though and the main difference I see is the 1157 are a brass base with recessed contacts and the 1034 are bright metal with protruding contacts. Same as the ones in the car. The contacts on the car bulb socket wires are also protruding. The bulb pins look the same on both. I was trying this morning to find a metal brush to ream/clean out the socket although these look pretty good. Did not find anything to use but may hit them with some emery cloth. I'm not suspecting a short there but after all these years just want there to be a good contact and ground. Was also thinking of dismantling the lenses to get a better look at the wires where they lie on the inside of that housing. Process of elimination going forward in the car. As soon as I check with the OHM meter, assuming I do it correctly I will post the results. If it reads okay then I might have to go to another switch in the system. Like the brake light switch. There is an extra one with the spare parts so that might be the original. Just don't know what was done before. Like ONEOFMANY said his blew every time he hit the pedal. That was in play when these went out.
70 GTX-R
Active Member
- Local time
- 8:17 PM
- Joined
- Aug 13, 2021
- Messages
- 38
- Reaction score
- 120
- Location
- Winnipeg Manitoba Canada
This is what I do also. But I use a new small headlamp bulb, have enough wire to hang it from rear view mirror so easy to see. Also don’t want bulb touching anything it could melt. When there is no short, power going through will show as dim light as well as others in circuit. When short present will be full brilliance.
ynst
Well-Known Member
If you're not blowing the turn signal fuse, you can pretty much rule out the brake light circuit (with one exception) as the stop and turn filaments are the same in the 1034 or 1157 bulbs. From the turn signal switch all the way back to the tail lights it's the same pair of wires. One for the left stop/turn and one for the right stop/turn.
BTW, the 1157 is just a brighter version of the 1034.
The only thing different in the brake circuit is the wire coming from the brake switch to the turn signal switch. Look for a short to ground in this wire. It'll probably be where the wire runs across a brace under the dash.
If the fuse doesn't blow until you step on the brakes, there's a good chance that the brake switch-to-turn signal switch wire is the culprit.
The brake light switch on the pedal linkage is powered ALL of the time and only switches "on" when you step on the brake pedal at which time it sends 12 volts to the turn signal switch which, then, routs the 12 volts to one or both stop/turn bulbs depending on the position of the turn signal lever.
The courtesy light system is powered ALL of the time and the lights only come on when you complete the circuit to ground either through the door jamb switch or by activating the dome light switch in your headlight switch assembly. 12 volts from the fuse is present on ALL of your courtesy light bulbs as well as the glove box light. In some vehicles the clock is also on this fuse.
If the brake/courtesy fuse is blowing randomly when you aren't operating the brakes or the courtesy lights, then the culprit could be in the feed wire(s) to the various courtesy lights or in the feed wire to the brake switch.
Been out of print for over 20 years but is really helpful.....
BTW, the 1157 is just a brighter version of the 1034.
The only thing different in the brake circuit is the wire coming from the brake switch to the turn signal switch. Look for a short to ground in this wire. It'll probably be where the wire runs across a brace under the dash.
If the fuse doesn't blow until you step on the brakes, there's a good chance that the brake switch-to-turn signal switch wire is the culprit.
The brake light switch on the pedal linkage is powered ALL of the time and only switches "on" when you step on the brake pedal at which time it sends 12 volts to the turn signal switch which, then, routs the 12 volts to one or both stop/turn bulbs depending on the position of the turn signal lever.
The courtesy light system is powered ALL of the time and the lights only come on when you complete the circuit to ground either through the door jamb switch or by activating the dome light switch in your headlight switch assembly. 12 volts from the fuse is present on ALL of your courtesy light bulbs as well as the glove box light. In some vehicles the clock is also on this fuse.
If the brake/courtesy fuse is blowing randomly when you aren't operating the brakes or the courtesy lights, then the culprit could be in the feed wire(s) to the various courtesy lights or in the feed wire to the brake switch.
Been out of print for over 20 years but is really helpful.....
Mariposa Mike
Well-Known Member
Thank you. All these tips should get me through this. There is more than one issue with the wiring and who knows what was done before I got the car a few weeks ago. Fighting a starting problem as well. I suspect the relay on the firewall as it does not look to have been replaced but I suppose could be elsewhere too. PO was fighting these issues. I can tell by the notes he took and the extra parts. I hope this is not a hidden wire problem that requires dismantling half the car to get to it. And for anything under the dash I'm going to have to hire a 10 year old to crawl under there. Or at least remove the bucket seat.
BTW, is it possible the headlight switch can be an issue? When the fuse blew I don't believe it was being used but just thinking out loud. There is an extra one of those with the parts.
BTW, is it possible the headlight switch can be an issue? When the fuse blew I don't believe it was being used but just thinking out loud. There is an extra one of those with the parts.
Since you don't have a lot of knowledge of the history of this car, don't think you can rule anything out till you can get the time, and more reasonable temperatures to do further investigation and look into things that have been suggested.
Mariposa Mike
Well-Known Member
Accomplished a lot this AM before the heat and humidity hit. Should be on this tomorrow and report back.
Mike,
I feel your frustration through all these pages. What I've learned after 60 + years of messing with old cars and hot rods is DON'T GIVE UP! The solution will show up if you're diligent in your testing and do things methodically. When you do get it figured out you will get a self generated "atta boy" and a great feeling of self satisfaction. If it makes you feel better imagine trying to find the same problem in any one of a hundred different electronic circuits in a new car...
In case the problem keeps alluding you, check with your local O'Reilly's, NAPA or other parts store to see if there's a car club in the area. Could be Mopar specific but doesn't have to be. Car guys will always help other car guys...One of my sons lives in Turlock and there are several there or in Modesto. I feel you about the heat; 10 days in a row over 100* and 3 over 110*!
Hang in there...
I feel your frustration through all these pages. What I've learned after 60 + years of messing with old cars and hot rods is DON'T GIVE UP! The solution will show up if you're diligent in your testing and do things methodically. When you do get it figured out you will get a self generated "atta boy" and a great feeling of self satisfaction. If it makes you feel better imagine trying to find the same problem in any one of a hundred different electronic circuits in a new car...
In case the problem keeps alluding you, check with your local O'Reilly's, NAPA or other parts store to see if there's a car club in the area. Could be Mopar specific but doesn't have to be. Car guys will always help other car guys...One of my sons lives in Turlock and there are several there or in Modesto. I feel you about the heat; 10 days in a row over 100* and 3 over 110*!
Hang in there...
Dako
Well-Known Member
To add to the suggestions:
Wiring should run parallel to driver side door sill, (under the carpet there are two curved piece of metal protecting/ containing the harness). This is also an area to check for pinched/ grounded wiring. Good luck with your trouble shooting!
Wiring should run parallel to driver side door sill, (under the carpet there are two curved piece of metal protecting/ containing the harness). This is also an area to check for pinched/ grounded wiring. Good luck with your trouble shooting!
Mariposa Mike
Well-Known Member
I removed all the bulbs and my OHM meter does not have the Rx1 scale nomenclature. So I used the lowest setting on the dial which is 200 OHM. Connecting the OHM leads together is reads .3 and when I connect the leads to the car fuse load and a ground is reads 41.5. I looked at the back of the fuse block which is difficult to do as there is not much extra wire to pull this block down into view but saw corrosion on some of the connecters. Just the green stuff that is not significant but it is not a pristine block. So if I'm getting any reading am I finding the issue is in those lighting wires somewhere?
Mariposa Mike
Well-Known Member
One more update! I just found another light bulb in the center console. The OHM reading went down to 30 after I removed that bulb. So that and the glove box and trunk light are all now out of their socket. The passenger side console floor bulb and the one I just found inside the console had corrosion on the contacts and base but the wire housing looks okay. I'm hoping there is not another one somewhere I'm missing. External inspection looks okay at the bulb connections but I might remove what covers I can from the trunk, console, etc. It seems there is still some resistance somewhere.
Looking at schematic again, Sorry, but realize I failed to mentioned the rear license plate lamp in my earlier post. It's fed off the same wire (source) that feeds all the lower brightness filaments of the tail light lamps.
Mariposa Mike
Well-Known Member
Roger that. Will go after that next. Since the turn signal switch is in this chain, dash signal light bulbs would be in there as well would they not? Or maybe the switch has to be activated to pick up those bulbs and change the OHM reading. If those are included then the dash would have to come out. I may have to do that anyway to get the EL function working or cluster sent out for repair. Have not checked the power supply yet since I have been on this mission.
It might be worth lifting the rear seat also - the loom passes close to the framework of the seat - and a pinched wire could be hiding anywhere really.
Similar threads
