Stuck in the dark! ELECTRICAL

[boosd]

So a few months ago I took my car in because my parking lights failed after the wiring at the combo switch melted. I took it in, and had the switch and wiring replaced... Everything seemed fine, I took it out for the first time today and tonight when I got in it to drive home I realized my headlights and my dash lights arent working. I pulled took off the covering around the steering column/combo switch and began to look around and found a few disconnected wires. Got the Headlights working which is a start, but dash lights still arent working, I think something is incorrectly soldered/wired because when i went to adjust the dimmer knob, my parking lights are going dim or bright when turned... maybe something is just plugged in wrong, or not plugged in? I also found a connector that is unplugged and i am unable to reach far enough up to plug the two in.

Here are a couple pictures

1974 260z

[SteveJ]

The 74 headlight switch has one nine-pin connector (parking lights and wiper). It also has single connectors for a black wire (ground), white/red wire (power coming in for the headlights and parking lights/dash lights), and red wire (headlight power to the fuses). There is also a black wire (ground) with a connector that allows two wires to be plugged into it independently.

If you really think your headlight switch is hosed, you can actually still buy a new one. Rockauto has them for $157. I have one in my 260Z. Compare it to yours: More Information for STANDARD MOTOR PRODUCTS HLS1026.

First verify that you have a good, functional switch. Inspect the nine-pin connector closely. That's the one for the parking lights, and I have seen signs of overheating there.

What are the wire colors going into the unplugged connector?

Be sure to download the 74 FSM from the link below. The BE section does a very good job of breaking down the circuits for you to troubleshoot. In particular focus on pages BE-10 (headlights), BE-14 (parking lights), and BE-16 (dash lights). After comparing what the manual says to what you see, post your findings and questions, and we can probably give you a path from there.

[Mikes Z car]

The wire powering your parking lights now is probably the one that is supposed to go to the dash lights as they can be dimmed. The dimmer may not be able to handle the current of the parking lights for long and might burn out if left connected that way, I don't know for sure, just an idea.

Edited January 14, 2013 by Mikes Z car

[boosd]

The 74 headlight switch has one nine-pin connector (parking lights and wiper). It also has single connectors for a black wire (ground), white/red wire (power coming in for the headlights and parking lights/dash lights), and red wire (headlight power to the fuses). There is also a black wire (ground) with a connector that allows two wires to be plugged into it independently.

If you really think your headlight switch is hosed, you can actually still buy a new one. Rockauto has them for $157. I have one in my 260Z. Compare it to yours: More Information for STANDARD MOTOR PRODUCTS HLS1026.

First verify that you have a good, functional switch. Inspect the nine-pin connector closely. That's the one for the parking lights, and I have seen signs of overheating there.

What are the wire colors going into the unplugged connector?

Be sure to download the 74 FSM from the link below. The BE section does a very good job of breaking down the circuits for you to troubleshoot. In particular focus on pages BE-10 (headlights), BE-14 (parking lights), and BE-16 (dash lights). After comparing what the manual says to what you see, post your findings and questions, and we can probably give you a path from there.

So i looked at the 9 pin connector, and the wires going in (from the headlight switch) are different colors than on the other side of the connector plug, were the headlight switches across models different and this could be causing the problem?

(see below)

The unplugged connector is a 3 pin connector, but one of the 3 wires has been cut, so what remains is a red wire and black wire, (photo 3)

9 PIN CONNECTOR (FROM REPLACED COMBO SWITCH)

Gw Bg Bw

Bw By B

By B Br

9 PIN CONNECTOR (Original to wiring harness)

Yg Bg Gw

Bw Rb Wg

By B Br

Uppercase = Main Color

Lowercase = Stripe(if there is one)

G/g = Green

B/b = Blue

R/r = Red

W/w = White

Y/y = Yellow

(The Color diagram is meant to show the colors that are connecting i.e. first: Gw is connected to Yg)

Edited January 14, 2013 by boosd

[boosd]

So im thinking, based on looking at the FSM that the 3 pin connector that is unplugged might be the warning buzzer from the door being ajar. I am not the best at understanding the FSM so I dont know that i will give the most accurate answers based on that, but it appears that all my plugs and wires are correct, so I think either its something to do with a mis-mmatched combo switch, which I dont know if there are compatibility issues across models, i think the one in there now is from a 240z...

So the problem is that my dimmer knob is turning up and down my parking lights, and I have no illumination in my dash lights is this a simple plug? From the FSM, i dont see anything that is out out place

[SteveJ]

Okay, after looking at the wiring diagrams, I can say with fair certainty that your switch isn't the issue, even if it's from a 73 240.

By the way, here is the legend that Nissan used in the manuals.

B - Black

G - Green

L - Blue

R - Red

W - White

Y - Yellow

The first color is the main color of the wire and the second is the stripe (if any).

Let's use that convention since it will match up to the drawings.

Refer to pages BE-14 and BE-16 from the factory service manual. I'll trace out the circuit for you. Follow along on those pages.

The positive wire from the battery goes to the W wire at the starter. The W wire goes through the fusible link to the shunt. Out of the shunt, it is WR.

The WR goes throught connector C-6 into the body harness and on to the fuse box. It goes through a 20A fuse and out to the GL wire.

The GL wire goes back through connector C-2 and over to the connector at the combination switch at the steering column and into the switch.

The wire comes out of the switch GW. It should split once with one branch going to the parking lights and the other going to the dash lights. The branch going to the parking lights should branch again between front and back. The GW wire goes out to the bulbs and back to ground through a B wire.

For the dash lights, the GW wire branches to each bulb in the light string and comes out RL. The RL wires join together at the rheostat and from there, goes out a GW wire to ground in a B wire through C-4.

Unless someone crossed wires in the dash harness, I can't see how the dimmer switch could affect your parking lights.

[boosd]

So.... Got the car back from the shop today, and what i am being told is that the dimmer switch is failing in some way. I pushed and pulled on the dimmer switch a bit and the dash light came on faintly. Unfortunately the shop did not have a replacement switch so i will have to track one down somewhere and on the ride home i smelled a some burning and then the parking light fused popped and there went my parking lights Does anyone know what models i can choose from for this switch, i have an early 260z....

[SteveJ]

Okay, let's talk about some things here.

1. You have a short.

2. Your mechanic doesn't sound a good automotive electrician.

The part number for the resistor is 25950-E4601. Try ordering it from NissanParts.cc - Your #1 Source for OEM Parts and Accessories. That's a website for a Nissan dealer in the Bruce Titus group, and it's located in Washington state.

Meanwhile, here is your next homework assignment. Take apart your side marker lights. Look for corrosion in the bulb sockets. If there is enough corrosion, it can bridge the gap between the positive and negative terminals in the socket and essentially cause a short. Also inspect the connector between the combo switch and the dash harness. Look for any signs of overheating such as shown in the attached picture. Also inspect your fuse box for signs of overheating.

[boosd]

Ok, so months later..........

I order a new dimmer switch, replaced it and yep... still the same problem

Things that i have learned though are...

With the dimmer switch unplugged, the parking lights operate as expected no problems, when i plug in the switch everything functions correctly for about 2 seconds, then the dash lights dim, the Green/Blue wire begins to get hot, the parking light fuse gets hot, and just recently the green/blue wire got so hot it broke the solder...

Does this help any?

Im not a real technical person when it comes to electrical... and would love to have someone fix this for me, however the shops that i took my Z too basically told me they werent too sure about how to tackle this, which i didnt see as a great sign...

[SteveJ]

It means you have a short in the dash light harness. Start with checking EACH light socket. Look for corrosion (already mentioned) and crossed wires. Make sure no one did a makeshift repair on a socket and crossed the positive and negative wires. Make sure you don't have any damaged wires, too.

Do you know how to use a multimeter?

[ktm]

It means you have a short in the dash light harness. Start with checking EACH light socket. Look for corrosion (already mentioned) and crossed wires. Make sure no one did a makeshift repair on a socket and crossed the positive and negative wires. Make sure you don't have any damaged wires, too.

To add to Steve's suggestion, you are looking at the Red/Blue wire (at least on a 240z) in the dash harness as well as the sockets. The Red/Blue wire feeds power to the dash lights from the dimmer.

[boosd]

It means you have a short in the dash light harness. Start with checking EACH light socket. Look for corrosion (already mentioned) and crossed wires. Make sure no one did a makeshift repair on a socket and crossed the positive and negative wires. Make sure you don't have any damaged wires, too.

I have check all the light sockets and never found a problem, previously there was a problem that caused over heating from the headlight and melted the 9 pin connector, so the headlight switch was replaced, and im guessing there might have been some make shift patch work....

Do you know how to use a multimeter?

Never used one

Edited April 30, 2013 by boosd