Headlight/ tail light problem

[Take Warning15]

I rewired my 75 and put about 200 miles on it since without problem. The tail light bulb burned out once but I replace it an have had no problems until now. The headlight keeps blowing a fuse and I noticed that te tail light is fine until I put on the brake light. It gets incredibly hot and started melting the plastic light housing. It is an after market light but I've been using it for a long time without issue until now.

Electrical seems to be my weak point so if someone could explain to me what is happening I'd appreciate it. It's drawing too many amps? Why? How do I fix it. Could the headlight problem be fixed with a higher amp fuse? What about the tail light that keeps burning out?

 

[member3480]

Do you have three wire or two wire lights. Some of the aftermarket lights are only two wire and you are using the bolt attachment as the ground. Run good grounds all to one location and tie them into battery ground and you may fix your problem. I posted before that if you scrape the back of the frame and you scrape the neck and put a ohm meter on the lowest scale you mat not move the needle because of the rust inside the frame. I done this on a couple and nothing from front to back so when I make up harnesses all the grounds go to the motor and battery. If you have a two wire light just drill a hole and put a screw in it so you make the light frame the ground to a good ground. Very common problem

 

[Take Warning15]

I have a three wire tail light and it is grounded directly to the battery.

 

[member3480]

then I would take the light apart and see if all the wires are connected . Do you have a ohm meter?? you can trace your ground to see if its good.

 

[Take Warning15]

I did re solder the wires inside the light housing and it looks okay. Could this be caused by a short circuit somewhere? I do have an ohm meter. How can I check my ground?

 

[member3480]

You have to go threw the ends one end to the other if wire got hot enough it may have popped inside and you can't see it just like a fuse able link does

 

[fredintoon]

Hi,
sure sounds like the wiring has worn through someplace to create a short circuit and all that fitting an oversize fuse will do is let the short circuit start a bigger fire.
Like Daddy sez, you and your multimeter gotta find the bastard.
Mr Stupid trapped a wire under a clamp one time and it's insulation took some months to finally extrude enough to short the wire out.
Bought me a whole bunch of electrical parts to replace the usual suspects before I thought to check the wiring.

 

[Take Warning15]

How many amps should the fuse for te headlight and tail light be? On separate circuits.

 

[fredintoon]

How many amps should the fuse for te headlight and tail light be? On separate circuits.

Hi,
up to the late model E there was only one fuse to rule them all, one fuse to bind them - - - it was a 20Amp.
Late model Es and on had a 20Amp main fuse and 3 10Amp fuses downstream of it to protect different circuits so you didn't lose all of it at once.