NewbVetteGuy

While trying to figure out which of the 3 wires going into the amber parking lamps that I need to tap into to power the LED halos for my healights, I somehow blew the fuse.

I've pulled down the Wilcox fuse box diagram but none of the descriptions call out parking lamps... Anyone know?


http://repairs.willcoxcorvette.com/1...te-fuse-panel/


Even more confusing: I saw a spark and heard a definite "pop" when the fuse went. The first fuse I checked was the 20 amp tail-lamp fuse- it was definitely blow- I replaced it and fully expected the parking lights to work again, buy no dice.

The interesting thing is that with the fuse blown the brake lights still worked. ("tail-lamp" to me, means brake lights; no?)



Adam

NewbVetteGuy

No idea if it's accurate, but this PDF lists all / most 1979 Chevy fuse boxes and it lumps "tail", "side marker", "parking", and "underhood" all under the "Tail Lamp" "M" breaker in the Wilcox diagram....

http://vintage.mitchell1.com/PClubDa.../V2D793035.pdf

That honestly makes the most sense but I just replaced the fuse and it's still not working...

Time to pull the fuse and test it out of the car.



Adam

NewbVetteGuy

The plot thickens: I replaced the correct fuse, but every time I test the socket, it blows a fuse....


There are for some reason 3 wires going into the parking light; blue and brown feeding the two posts at the bottom of the bulbs and a 3rd wire going to the outside of the light bulb housing- I assume the black one is the ground??

I have no idea why a light bulb requires 3 wires, nor why testing it blows a fuse. I've killed 20 amp fuses and a 25 amp fuse so far; I stopped testing on my last 30 amp because I actually want to make this work.


I've got a ton of electric experience with AC 120 and AC 240; but haven't really messed with DC current before; maybe I'm doing something obviously dumb.

My regular AC current multitester didn't work with the DC current so I bought a bosch @ the auto parts store. It has the normal "com" black terminal and then two red terminals- one that says it's 250 mili amp max "fused" and the other that says it's unfused.



I really can't figure out why the act of testing the circuit would blow a fuse...


Adam

bazza77

front lamp should just have one 2 filament bulb , one filament will light when parking /headlights on . the other will flash with indicators. black=ground

You say bulbs , kinda makes it confusing to help . Unless they changed in 79 .

TimAT

Typical GM wiring color scheme is brown for tail, turn, marker lights, then blue, green yellow for turn, stop and black for ground.

GM used the "tail" marking for the tail lamps, marker lamps and park lamps.

NewbVetteGuy

One on the driver's side + one on the passenger's side = 2. 2=plural, which means you add an "s" to "bulb" to make "bulbs".

I never expected plural nouns would cause such confusion; or should I say, "I never expected that a plural noun would cause such confusion?".




Adam

NewbVetteGuy

That makes sense; there's two ways to illuminate the bulbs:
1st. via opening the headlights 1/2 way to the "park" setting
2nd. via hazard flashers


So two "hot" wires in to each bulb housing and 1 ground; that means when I'm measuring the voltage across the two hot wires I'm shorting the hot wires, hence killing the fuses, too. (Although the part of the multimeter I'm using is only supposed to pass 250 milliamps through the multimeter so it shouldn't blow a fuse...)

I'm thinking that if I carefully touch just one hot wire and the ground I should get a good volt reading without blowing a fuse??....


Adam

TimAT

Correct. 2 hots and a ground. Sort of a 220 VAC. Your meter should have a VDC setting. Use that on the lowest scale above 12v, then ground the black lead to whatever, and probe with the red for 12 VDC.
Strange that you popped a fuse. The only reason I can think of is that you had the park lights on looking for power, and when you hit the T/S lead the power was feeding back to the system and wanting to power the stop/turn side of the bulbs and was more than the fuse was happy with. Or trying to use both probes in the socket and hit the ground. That's easy to do- not much room in there.

And-- http://repairs.willcoxcorvette.com/?attachment_id=2549

bazza77

very clever of you, you know the 79 has one per side , I didn't , so good luck with all your future problems

NewbVetteGuy

Dapper 575s with Modern Led Halo- I would've preferred a traditional halo ring, but I got a 50% off deal 2nd hand that I couldn't pass up. 55 watt HID low beams and traditional high beams in a HID-style housing; white modern LED halos on all 4 activated via parking lights switch. (Vacuum override switch under the dash used to pop open the headlights when only the parking lights are on.)

Thanks everyone! I figured it out; still not sure if this is normal but I figured it out.


When I measure between the brown and the black ground with the parking lights on I get 11.something volts; when I measure between the blue and the black ground I get like 5 or 6 volts (that seems odd; this is NOT with the hazard lights on...). -When I measure between the brown and the blue I blow a fuse.

I cut into the parking light's brown and black wires and used crimp shrink connectors to add 2 red wires to each side's brown wire and 2 black wires to each side's black wire. Each pair of wires then goes to that side's 2 LED halos.

I tested em and they work! Yea! -Right now they're just mocked up with the wires twisted together. I've ordered some water-proof quick disconnect electrical connectors to connect each halo to my hacked harness; they should be here by Friday and I should be able to get them properly wired in and then install the hid ballasts and get everything fully finished up.



Adam

TimAT

A suggestion-- stop by Lowe's or someplace like that and get a roll of self fusing silicone tape. Make your connections and then wrap them with that. It seals like you wouldn't ever believe. No chance of water getting in.

1977Orange

Your front sockets have 3 wires because the light blue on one side and dark blue on the other side are your directional signals(blinkers).

vettebuyer6369

You are responding to a post from 3 years ago.