Fuses keep burning out. . . .

[alt76]

Hi I'm new here. Thought I'd see if anyone could help me out or make recommendations on the issues I currently noticed.

I recently converted my externally regulated alternator to an internal one on my 1972 Chevy K10 pickup truck. It's a 1/2 ton with a 350 engine, in case you need to know that info. Well I followed this video http://bit.ly/2mTgXMq and worked like a charm, BUT all of a sudden I no longer have parking/tail lights of any kind, as well as, the lights on my instrument/dash panel. I did find two fuses (the old glass cylinder type) that had blown/burnt out, so I replaced them. Well those blew out again. Any ideas? Is the new internally regulated alternator sending out too many amps that those fuses cannot handle? Do these trucks have a relay for these specifically (the parking/tail lights)? I just cannot figure out what is going on and with electrical, I'm at a loss at this point.

Look forward to your help!

[custom10nut]

I'm no electrical expert, but somehow you're shorting the circuit to blow the fuses.
Do a search on Alternator conversion, and I'm sure you'll find a thread that will help.

[VetteVet]

Located in the fuse panel is the tail/stop/park fuse and the Pnl Lts fuse. are these the two that are blowing?
They are powered by a red wire from the battery/alternator junction in the engine compartment.
These two fuses protect the wiring for the lights you say are not working when you turn on the headlight switch.
They are powered by a series of orange wires from the fuse panel to the dome light,stop light switch, and the headlight switch.
A short anywhere in these circuits will blow these fuses.

One of the most common places for a short is under the drivers side sill plate under the door. The orange wire for the dome light power runs under the sill plate and commonly the insulation will wear off it and ground on the rocker panel.

Do you have a multi-meter or a test light and know how to use them?

Take your positive battery cable off and turn on the headlight switch, parking lights should be enough if that's where the fuses blow.

touch your test light or MM on one end of the fuse holder and the other end on the ground. If you get a light or the MM reads zero ohms continuity then that is the circuit that"s grounded. Then do the same to the other end of the fuse holder.

If the dash light circuit is clean then you can unplug the rear lights plug behind the distributor in the firewall,and re-test. If the test is clean, then the short is in the rear harness, and if it isn't, and still reads zero ohms, then the short is in the front park lights circuit, which is a purple wire from the firewall plug to the two lights.

I agree that you don't have a problem with the alternator conversion since the light circuit is not connected with the charging circuit.

[alt76]

ansswers/replies in RED

Originally Posted by VetteVet

Located in the fuse panel is the tail/stop/park fuse and the Pnl Lts fuse. are these the two that are blowing? Yes
They are powered by a red wire from the battery/alternator junction in the engine compartment.
These two fuses protect the wiring for the lights you say are not working when you turn on the headlight switch.
They are powered by a series of orange wires from the fuse panel to the dome light,stop light switch, and the headlight switch.
A short anywhere in these circuits will blow these fuses.

One of the most common places for a short is under the drivers side sill plate under the door. The orange wire for the dome light power runs under the sill plate and commonly the insulation will wear off it and ground on the rocker panel. Does this orange wire lead to the dome light, I am assuming so since you mentioned it, but I ask because I want to trace it to look at it thoroughly to see if there is any wear/tear. I did take off the door sill and it was rusted underneath and could tell there was alot of moisture as well as on the carpet.

Do you have a multi-meter or a test light and know how to use them? Yes we are going to do that next after we check the orange wire. I'll keep you posted. THANK YOU!

Take your positive battery cable off and turn on the headlight switch, parking lights should be enough if that's where the fuses blow.

touch your test light or MM on one end of the fuse holder and the other end on the ground. If you get a light or the MM reads zero ohms continuity then that is the circuit that"s grounded. Then do the same to the other end of the fuse holder.

If the dash light circuit is clean then you can unplug the rear lights plug behind the distributor in the firewall,and re-test. If the test is clean, then the short is in the rear harness, and if it isn't, and still reads zero ohms, then the short is in the front park lights circuit, which is a purple wire from the firewall plug to the two lights.

I agree that you don't have a problem with the alternator conversion since the light circuit is not connected with the charging circuit.

[alt76]

Here are some photos (sorry they are very large) I had my wife took to see if you can tell me if we installed our alternator correctly. She mentioned to me she read on the made electric website about "clocking" position and it appears mine is not in the four positions (12, 9, 6 or 3)....would that matter? Oh and the red wire is in the #2 position on the back of the alternator and the white is to the #1..that white cable is spliced (or however you refer it as) to the #1 blue cable in the terminal that originally snapped into the voltage regulator.

Also there is this brown wire I took a photo off with what appears to be a fused link, is that right? Could it be possible the black fuse when bad? We took photos and zoomed in on it and it has a "400 and either a 1 or a letter L (can't really tell) and on the other side it has "ON".

[alt76]

Well after testing and retesting all of a sudden everything works. I don't even know what I did...by freeing up wires, etc and testing and resecuring, the park lights, tail lights, brake lights working. I'm happy and not happy cuz I have no clue what just happened. LOL