Electrical Help

[Ramses]

Hi,

I was hoping for some help. A bit of a story. Restoring a 73. I had to replace the wiring harnesses all the way around. Basically I had to purchase 2 of each and piece one together. I was moving right along till I tried to start her. The voltage regulator shorted out the chasis. I forgot to install the plastic piece behind it. I purchased a new regulator. Installed it, but here is the problem. Horn, lights and flashers all work intermittently. Flashers and horn work better than lights. I have traced power throughout the car and there is power going everywhere except when they are not working. When they are not there is power going to the relays but nothing past. The question is could the short on the voltage regulator short out the relays, or is there something more dramatically wrong here?

Thanks for your help.

Chuck

[240ZX]

Well, it seems as though a multi-meter and test probe are going to be your best friends here! Don't you just hate it when this stuff happens? My best advise is to go through and recheck all your grounds first and then look for any fried wires that may be intermitantly shorting. Check the relay too as a power spike, caused from your reg short, may have damaged them....maybe! These electrical issues can drive you to drinking! I would think that someone else will jump in and add some advise as well. By the way, welcome to the site and keep us posted on what you find! Good luck.

Tom

[Ramses]

Well I think that I have figured it out. It took me hours of tracing the circuits, but the only place that I have not replace or repaired is the combination switch. It is wired incorrectly. I turn on car, turn on lights and wiggle the wires and everything works. Wiggle the wires some more and nothing works. It was much easier than pulling the dash out again.

I have one more question. If I bypass my accessory relay all of my accessories work. When I use the relay, it grounds out and nothing works. Does anyone know if the relay is supposed to ground out, or is that the signal that it is blown. There is a wire comming out of the back of it and it hits the cover. If it is blown, where can I find another?

Thanks

[sblake01]

Could you post a good picture of the relay you refer to? I have several misc. relays and I might have a couple of those.

[Ramses]

Sblake01,

I do not have a pic as of yet, but It is a metal relay with 3 black wires coming out of it and those 3 wires go into a 4 wire plug. I will get a pic sometime tomorrow or this evening.

[sblake01]

Well, I looked through my junk and the only non 810 or 280Z relays I could find are three that have a 4 wire plug but they don't fit the description you gave. The have 4 wires, Black, blue/red stripe, white/red stripe, and red/blue stripe going into a 4 wire plug. I can read the part number on a couple of them. It's 25230-E4100 which is, according to the microfiche, the relay for the rear window defogger up to 11/74. Oh well If anyone needs one of those, I've got them.

[Ramses]

Steven,

Thanks for looking. Unfortunately, I already have 2 of those relays. I can not get them to work. They just click.

chuck

[sblake01]

The strange thing is, that the wiring diagram shows that relay as the accessory relay.

[Ramses]

Then the diagram is not for a 1973. The 73 only has 3 wires going to it.

[EScanlon]

Chuck:

The Accessory Relay DOES have 4 wires. Your fourth wire is the one that "grounds" to the case, and without the relay being mounted with a sheet metal screw to the metal on the kick panel, you're not going to get it to work...period.

That you've got 3 BLACK wires, whereas the schematic for a 73 show 3 BLUE wires may be a case of a replacement part. Check the colors of the wires on the connector that it connects to and see if they are the colors Stephen mentioned.

But aside from that, the accessory relay for your car ONLY powers the Heater Fan. The Rear Window Defroster has it's own relay, which also receives power from the same wire that powers the Accessory Relay, but they're independent of each other, otherwise.

Since you've nominally traced the problem to your Comb. Switch by wiggling and causing the fault, check for the following: a loose wire at the solder joints on the switches themselves; disconnect and clean off the bullet plugs on the bullet connectors and ensure they're a tight fit; do the same for the multiple wire connectors. While you're doing that check for loose wires and obvious signs of melted / scorched wires.

FWIW

E

[sblake01]

Then the diagram is not for a 1973. The 73 only has 3 wires going to it.

The bottom of the page reads 'Wiring Diagram - 240Z (Late model S30 series U.S.A. - manual and automatic transmission)'. The wiring diagram for the early cars also shows the same relay.

[EScanlon]

I do have two diagrams for the 73, one AT the other MT, both showing the Acc. Relay as only having 3 Blue wires going to it. The ground for the coil is showing terminating at the outline of the relay...and I presume that implies it grounds to the case.

Since the Acc. Relay HAS to close the circuit to ground in order to provide power is why it HAS to be grounded via it's mounting screw.

All the other diagrams show 4 wires to the relay in the colors Stephen pointed out. I didn't pay much attention to the wire color differences AT the relay ( that is, wiring not part of the actual harness) as that's always been difficult to pin down. The schematic and harness will match, but individual components won't necessarily show the same colors as what they connect to on the harness.

FWIW

E