half of fuse box dead

1970cat

Senior Member
FCBO Gold Member
Joined
Dec 10, 2012
Messages
3,408
Reaction score
3,010
Location
central ny
69 fury- what would cause the right side of the fuse box to be dead? everything on the left side works ok,car turns over, but no juice to the right side. service manual is not much help. (have to say that mopar wiring diagrams are not presented very well compared to gm.)
does power come from ammeter leads?
 
More than likely you have an ignition switch gone bad or wiring from the switch to the fuse block. With the key in the run position do you have power on all but one wire (yellow) coming from the ignition switch? Mainly you are wanting to check the blue wire from the ign switch.
 
Without a diagram in front of me I'm pretty sure one side in the pre ignition things like lights, the other the accessories that need the key on so yes, most likely the ignition switch.


Alan
 
ok, here we go. after much searching and a little luck i found the black wire on the back of the ignition switch had a broken crimp terminal. replaced the crimp and i had power. put the dash panel back in to try the function of the switches. turned the key on-had power for about two minutes then dead on right side again.took the panel back out. thought maybe the lack of black wire had damaged ignition switch. changed the switch-had power again-for about two minutes- dead on right side again. #@!&#@. any ideas?

now on to other electrical gremlins found while testing (for about two minutes).

courtesy lights- they also work for about two minutes and then blow the fuse. would a bad delay relay cause that? i wouldn't worry so much about the courtesy lights but they are tied into the running lights which i need.

dash flood lights-don't work. i am confused on this because i can't see how they would work. they are linked on an orange wire connected to another orange wire which appears to lead to the fuse box. the dash dimmer switch though has a double yellow and a yellow w/black tracer. no orange. the door jamb switches , ignition light , map light are yellow wires. it would seem that the dash dimmer would dim the courtesy lights and not the flood lights, maybe?

when things were briefly functional with the replacement switch,i noticed that turning the ignition to start would not start the car but would cause the power window relay to clunk.
the replacement switch came from a running car so it worked.

hopefully someone has some ideas. my back and neck hurt from crawling under in and around the dash. i have a headache from staring at wiring diagrams and my arms are ripped to shreds.
 
Just something to check out...under the hood... Disconnect the fire wall wiring connectors going to the bulk head, Go inside the car unbolt the bulk head/fuse block from fire wall, look behind fuse block for burned and shorted out melted together wiring... Also check the plug in connections for melted plastic and bad connectors!!! Good Luck!!
 
Ignition switch....

If broken it can make contact for some time ( time will vary) but as the connection in the switch is loose or the insulator back is broken, the resistance it has because of a bad contact heats the connection until it breaks contact.... When it cools, everything is fine... Until.... The right side of the fuse box goes dead.

Hours of fun diagnosing this and an absolute ball of fun when the car stops dead on a busy highway off ramp....

Just finished installing a replacement in my Road Runner. Another barrel of laughs.
 
If you are only loosing power on half of the fuse block I am pretty sure that it is not the bulkhead connector but I would pull it apart under the hood to make sure that its not starting to burn up as many of them did. What all are the fuses that are loosing power when this happens? I am still pretty certain that it is either the ignition switch or the wiring to and from the switch if you are loosing power on one side of the fuse block.
 
they are the accessory fuses. red wire is power to batt side of box . the black wire is acc. the second switch was a known to work one. i think the next step is to pull the fuse box apart and check continuity between there and the switch. seems like it works just long enough to get warm and then it dies.
 
Yeah sounds like a broken or almost completely broken wire. It is possible that when you check it will have continuity on the wire but still not be good. If there is one strand still ok in that wire it will show continuity but will not carry the current needed to supply the fuse block. So keep that in mind when checking.
 
Wiring can be the reason for a lot of cars purchased very cheaply.. Have bought a few in the past with wiring issues and fixed them up fora nice tidey profit!

It's all about the connections... check every single one you can find!
 
ok, been poking around with the test light

when i have full power to the fuse box if i touch the test light to the black w/white wire on the back of the headlight switch it will short out and kill everything including the feed into the fuse box which i believe comes from the starter relay. tried two different switches same results. keep in mind that i have the switch hanging loose (not grounded). also have power to the crimps on the back of the headlight switch that hold it together. not sure if this is a grounding issue.

strangely enough when i lose power to the acc side of the fuse box i still have power to the brake light switch ( pink wire). if i push on the brake pedal i lose power to the entire fuse box. let up on the pedal, power comes back.

i guess smoke coming from the dash dimmer means it is bad :)

found a broken connector on the hazzard switch
 
progress:

a new time delay relay got the ignition light working

dash dimmer sent out for refurbish

bad connection in the dash courtesy light - fixed that.

new flasher unit got those working. switch is a little crusty, but they work

exterior lighting, usual combination of crusty sockets, blown bulbs and broken wires

power top working, power windows working.(well, power to the windows at least)

blown fuse for the courtesy lights and park lights. not sure why it blew. spent half a day trying to duplicate it but couldn't.

now for the fuse box- seems that the ammeter is cutting out at random times. sometimes 5 minutes but today it worked fine all day. search is on for a new one.
 
ammeter it was. pulled the cluster apart and there was rust in between the lugs and the ammeter itself.too much resistance and signs of blackening so i think i caught it just in time
 
Check that there is a good connection on the shunt wire between the two sides of the fuse box. One side
is high amperage the other lower accessory amperage.
 
ammeter it was. pulled the cluster apart and there was rust in between the lugs and the ammeter itself.too much resistance and signs of blackening so i think i caught it just in time

Just get rid of that fire-starter circuit altogether.
 
i don't think there is anything inherently wrong with ammeters. there were millions of mopars built from the thirties through the late seventies with ammeters. not to mention everything from farm tractors to lawn mowers. i understand that was a long time ago, but if the connections are clean and sound i see no reason why they would catch fire.
 
Back
Top