2nd Gen Non-Engine/Transmission fuse 20/stop lamp, keeps blowing

[AKington]

About two weeks ago I was driving home and noticed my dash abs light and brake light were on. I drove it home and discovered fuse 20/stop lamp fuse was blown. Everything worked fine until today when it did the same thing. I went to auto zone and bought two 20A fuses, I blew both of them in the parking lot. It seems to have something to do with hitting the brake pedal or putting it into drive, at least this time. Also the lights are actually flashing at certain times when I am parked, kind of like turn signals. Any ideas on what might be causing these problems?

 

[Missouri Mule]

AKington, Looking at 96 FSM. Fuse 20 supplies power to stop lamp switch thru f32. When the switch is closed it connects f32 to L50 which supplies to power to the high mounted stop lamp and to the multi-function switch which sends power to the stop lamps on the back of the truck thru L62(right) and L63 (left).

f-32=pink/dark bue, L50=white/tan, L62/63=dark green/brown.



Could be short since your blowing fuses but brake lights flashing sounds more like the Multi-function switch.

 

[AKington]

It's not the actual brake lights that flash. The brake lights, turn signals, etc. don't work when the fuse blows. It's once I start the truck, the dash abs and dash brake light are on. Then I wait a couple of minutes and those same lights will flash on the dash, they seem to be in unison. They don't flash all the time. I just noticed that if I mess with the turn signal I can get the dash lights to turn off, so it might be that multi function switch. When that switch goes bad will it short and blow the fuse?

 

[Missouri Mule]

Don't know! But possible, the Multi-Function switch can do weird things.

When your brakes light go out that mite be why your abs brake warnig light are flashing. Just letting you know that you have a probelm that needs to be taken care of right away. (The abs and brake waring light have been known to go on when one brake light is out. )

 

[AKington]

Ok. I just thought it was weird the dash lights would flash at all. I guess I will replace the multi function switch and see what happens. Thanks for the input.

 

[AKington]

Just an update. I found a 20A fuse and put it in the stop lamp. I started the truck and didn't touch anything. No abs and brake dash lights came on. So I moved the turn signal trying to get the fuse to blow and noticed no turn signal lights on the dash. I turned on the hazards and no hazard lights on the dash. I thought this was weird because the abs and brake dash lights were not on. So I turned off the truck and checked the stop lamp fuse and it was still good. So I pulled fuse 6/ Turn signal and it was blown.

 

[Missouri Mule]

I still would check for shorts still. But things are pointing to the multi-function switch.

I thought since your brake lights were not flashing it mite be the brake light switch or a short.

 

[HHhuntitall]

IN this case, I'd start under the bed at the back by the tail lights. It sounds to me like you have a bright side bulb wire rubbed into a turn signal ground or feed wire. I've seen several where those wires rubbed into where they go up from the frame up to the lights... . somewhere in there. A melted bulb socket could do it, as well. Secondly, I'd check the trailer plug, if you have one. A small wire not properly seated in the sockets in the back could cross over and make a short, but this doesn't sound like that situation. There could be an abrasion rubbed wire on the frame somewhere, too, but usually it's at the back. Lastly, I'd suspect the multi-function swith, as if it's not stiff or clicking unusually, failing to lock in up or down positions, I doubt it's malfunctioning. It has to have something broken inside or some foreign objects in it for it to short out. Also, check and see if the light on the back of the cab is lighting up. It will light even if the fuse is blown for your tail lights. If it's lighting properly, I'm gonna say for sure it's in the wiring for the brake/turn signals.

 

[budnate]

this is good info for sure, fyi my flasher relay shorted last fall internally and caused the same issues, had a spare in the shop, plugged it in and all was well.



B.

IN this case, I'd start under the bed at the back by the tail lights. It sounds to me like you have a bright side bulb wire rubbed into a turn signal ground or feed wire. I've seen several where those wires rubbed into where they go up from the frame up to the lights... . somewhere in there. A melted bulb socket could do it, as well. Secondly, I'd check the trailer plug, if you have one. A small wire not properly seated in the sockets in the back could cross over and make a short, but this doesn't sound like that situation. There could be an abrasion rubbed wire on the frame somewhere, too, but usually it's at the back. Lastly, I'd suspect the multi-function swith, as if it's not stiff or clicking unusually, failing to lock in up or down positions, I doubt it's malfunctioning. It has to have something broken inside or some foreign objects in it for it to short out. Also, check and see if the light on the back of the cab is lighting up. It will light even if the fuse is blown for your tail lights. If it's lighting properly, I'm gonna say for sure it's in the wiring for the brake/turn signals.

 

[AKington]

Ok, I took off the rear left tail light off and found a groundwire not attached to anything. Does anyone know where it should connect? I didn't see a ground screw or another wire it looked like it should attach to. I just put electrical tape on the wire and put it back together. I didn't have a 20A fuse for fuse 6/turn signals, so I put a 15A in. I started the truck and everything besides the hazards seem to work. Fuse 20/ stop lamp is not blown, so no abs and brake dash lights. Fuse 6/ turn signal is not blown so I have turn signals. Is it the 15A fuse not allowing the hazards to work or did I just blow a fuse, etc. somewhere else?

 

[AKington]

Where is the flasher relay? That's interesting because when Fuse 20 was blown, the abs and brake light on the dash were always on but would flash at times. I don't think those lights are supposed to flash at all right?

this is good info for sure, fyi my flasher relay shorted last fall internally and caused the same issues, had a spare in the shop, plugged it in and all was well.



B.

 

[Ram4Sam]

Ok, I took off the rear left tail light off and found a groundwire not attached to anything. Does anyone know where it should connect? I didn't see a ground screw or another wire it looked like it should attach to. I just put electrical tape on the wire and put it back together. I didn't have a 20A fuse for fuse 6/turn signals, so I put a 15A in. I started the truck and everything besides the hazards seem to work. Fuse 20/ stop lamp is not blown, so no abs and brake dash lights. Fuse 6/ turn signal is not blown so I have turn signals. Is it the 15A fuse not allowing the hazards to work or did I just blow a fuse, etc. somewhere else?

To me, the scotchlock says that a previous owner scabbed in a trailer light connection or maybe some running lights, get rid of it.



Sam

 

[AKington]

Ok, I will.

To me, the scotchlock says that a previous owner scabbed in a trailer light connection or maybe some running lights, get rid of it.



Sam

 

[HHhuntitall]

To me, the scotchlock says that a previous owner scabbed in a trailer light connection or maybe some running lights, get rid of it.



Sam

Yeah, looking at it, I can't tell if it's the ground or brake light/turn feed. If it is the bright bulb element feed, it would explain why it would blow one fuse or the other, and would be intermittent, as it would only ground out when you had one or the other on and it made contact with some metal in there. Likely, at one point or another, someone was using that as a source for a trailer or auxillary light. When they sold the truck, they probably pulled the accessory, but just left the wire hanging, or had some tape on it, which fell off recently, leaving you to deal with it. I'd check the other side, too, as it's likely the same way.



Your flasher is inside your fuse block door. There are two, one for the turn signal, and one for the four way flashers. I believe the one lower towards the front is the one for the flashers. Also, the 4 way flasher switch is prone to corrode from moisture and dirt coming in from the top. Switch it up and down several times quickly, and see if it starts working, if the flasher relay is in it, that is.

 

[AKington]

From the diagram I was looking at, it is a ground. The other side seems stock, I don't see anything similar. I just swapped the 20A horn fuse with the 20A Hazard fuse in the pdc. That fuse must have blown around the same time fuse 6 did I guess. Everything seems to finally be normal. I am going to drive it to work today and see if it stays that way.

Yeah, looking at it, I can't tell if it's the ground or brake light/turn feed. If it is the bright bulb element feed, it would explain why it would blow one fuse or the other, and would be intermittent, as it would only ground out when you had one or the other on and it made contact with some metal in there. Likely, at one point or another, someone was using that as a source for a trailer or auxillary light. When they sold the truck, they probably pulled the accessory, but just left the wire hanging, or had some tape on it, which fell off recently, leaving you to deal with it. I'd check the other side, too, as it's likely the same way.



Your flasher is inside your fuse block door. There are two, one for the turn signal, and one for the four way flashers. I believe the one lower towards the front is the one for the flashers. Also, the 4 way flasher switch is prone to corrode from moisture and dirt coming in from the top. Switch it up and down several times quickly, and see if it starts working, if the flasher relay is in it, that is.

 

[Ram4Sam]

If that is a tap into the ground leg of the lamp fixture, it may be because the previous owner was having an issue with the taillight that was diagnosed as a grounding issue for the tail light. Instead of chasing the grounding issue in the truck's wiring harness and fixing it, that is a mickey mouse way to ground the tail light so it would work.



Sam

 

[AKington]

Well it must have been the exposed ground wire. Since I put electrical tape on it, I have had no more problems. Thanks for all the replies.

 

[PBJ2500CTD]

Well it must have been the exposed ground wire. Since I put electrical tape on it, I have had no more problems. Thanks for all the replies.

From the picture it is difficult to see the color of the wire that was tapped but a "shorted" ground wire - to ground - will not blow a fuse. However, looking at the left bulb socket wiring pin-out in the FSM, the tapped wire would be for the left turn signal/brake, which would have caused the fuses to blow when the exposed conductor grounded out and your brakes were applied or left turn signal was activated, which blew the respective fuse(s). I agree with suggestion to remove the scotch-loc and seal the insulation to prevent corrosion of the conductor.

 

[Ram4Sam]

After you remove the scotchlok, get a hammer and beat the scotchlok into little pieces, as they all should be... .



Sam

 

[HHhuntitall]

After you remove the scotchlok, get a hammer and beat the scotchlok into little pieces, as they all should be... .



Sam

..... I second that motion... ... repeatedly.