Putting Dashboard back in, parking light fuse keeps blowing

[dpascual1986]

I am in the process of putting my dashboard back into the car (1973 240z), I didnt label the connections (bad mistake, I know)

Everything seems to work, except my dash lights. My current issue is that I keep blowing the parking light fuse (third one down from the right, MSA fuse box) when I turn the dimmer switch.

Any suggestions on how I should approach my issue?

Edited September 17, 2013 by dpascual1986
forgot to put what year

[SteveJ]

1. Disconnect all the dash harness connections.

2. Use the factory service manual (FSM) to help you match up the connectors. Hint: The wire colors should match on each side of the connectors.

3. As you make each connection, use an ohmmeter to check resistance to ground at the fuseholder. When the resistance drops, you know you found the circuit with your problem.

4. If you don't see an obvious issue, note the wire colors on each side of the connectors that caused the problem and let us know, along with the number of wires and shape of the connectors. (Pictures help!)

[dpascual1986]

3. As you make each connection, use an ohmmeter to check resistance to ground at the fuseholder. When the resistance drops, you know you found the circuit with your problem.

Im assuming that I know which circuit is problematic -the one with the blowing fuse (or am I wrong to assume this?)

I will match colors tonight... I tried to do this as much as possible but with a color vision deficit and a 40 year old car with dirty/faded wire colors, things are not as easy as stated.

[SteveJ]

Something is causing a dead short on that circuit.

As for dirty wires, Simple Green, Purple Power, etc., work great to remove 40 year old dirt to reveal wire colors. If you have trouble discerning colors, get a friend to help you.

[dpascual1986]

Something is causing a dead short on that circuit.

As for dirty wires, Simple Green, Purple Power, etc., work great to remove 40 year old dirt to reveal wire colors. If you have trouble discerning colors, get a friend to help you.

Will do, SteveJ. I will update next week once I get through the suggestions. Thanks for the quick replies and expert advice.

[dpascual1986]

So I just got my hazard lights working today...

is this normal?

the blinker seems slow, and it dims the parking lights. Any suggestions before I go at it again tomorrow afternoon?

[Mikes Z car]

In my experience when one circuit affects another like that it is because of a poor ground that the two circuits share. I don't know for sure about the

'73 model but my '70 model has a ground wire hidden behind the tail light finisher inside the car. There is a wire that comes from the tail light assemblies that goes to a screw near the middle of the car. Scraping the connection clean on the wire connector, the screw and the body of the car with a wire wheel or knife should help.

[dpascual1986]

In my experience when one circuit affects another like that it is because of a poor ground that the two circuits share. I don't know for sure about the

'73 model but my '70 model has a ground wire hidden behind the tail light finisher inside the car. There is a wire that comes from the tail light assemblies that goes to a screw near the middle of the car. Scraping the connection clean on the wire connector, the screw and the body of the car with a wire wheel or knife should help.

can you show me/tell me where this wire is?

[Kurbycar32]

If your front turn signals aren't hooked up or otherwise aren't working the flashing will be slower, which could be your problem. The flasher is actually a thermal device and if there isn't enough current being drawn through it the flasher takes longer to heat up, slowing down the action as you see here.

[Mikes Z car]

dpascual1986,

Sorry, I realized after that post that I didn't describe where that ground wire is.

Are both left and right tail lights doing exactly the same thing?

On my '70 model the ground for the tail lights appears to be where the green arrow points on the attached picture on the floor on a piece of metal that sticks up about an inch. On my 72 parts car all of the wiring, nuts and bolts have been stripped, I can't see an obvious separate place for the ground as on my '70 model. I notice on the '73 FSM electrical schematic the ground for the tail lights is shown near the fuel sending unit. I know there is no guarantee that that means the ground is near the tank sending unit but it might be a hint. The ground might be underneath the car on the sending unit. If you can't find a ground you could add one by connecting one end of a wire to the black wire on either tail light connector on the car harness side of that connector, see picture. The other end of the new ground wire would connect to the metal car body perhaps where the vertical support is in the middle (after hole is drilled and paint scraped off) with maybe a bolt, nut and lock washer to make it very secure. The wire would go to a "ring connector" or whatever they call those which would fit under the bolt. Or you could temporarily make this connection to verify it solves the problem.

If only one tail light is behaving that way the connector for that tail light assembly might be cleaned, especially the two halves of the connector for the black wire.

Anyone else see troubleshooting alternatives or solutions?

Mike

Ground location on my '70 model (hopefully this wasn't added by a PO)

New tail light ground connection:

Edited September 20, 2013 by Mikes Z car

[SteveJ]

I believe the ground will be found under the carpet in the back near the right taillight in the 73. However, my memory is fuzzy and is the carpet.

[dpascual1986]

If your front turn signals aren't hooked up or otherwise aren't working the flashing will be slower, which could be your problem. The flasher is actually a thermal device and if there isn't enough current being drawn through it the flasher takes longer to heat up, slowing down the action as you see here.

you are the winner sir, I havent connected the flashers in the front.

As for everyone else, I have found the grounding point in the back, and in the front, I will clean both, replace terminals and add grounding points this weekend and see where it takes me.

Does anyone have any opinions about this...? I am planning to get one to help with my short circuit woes..

Oh and I replaced my T/S flasher last night, it keeps clicking when my key is Off and on ACC but turns off when I switch to On (regardless of T/S switch position- up, middle, or down) Any clues which wire I may have crossed?

Edited September 20, 2013 by dpascual1986