SteveJ

I just bought some 5 LED bulbs through Amazon (Cutequeen LED Car Lights Bulb Green BA9 BA9s 5050 5-SMD BA9S, 53, 57, 182, 257, 1895, 6253, 64111, 64113 (pack of 2) : Amazon.com : Automotive). I had to remove the green filters in the gauges, but the light output is great. I'm going to buy some more to put in the speedometers and tachometers of my cars. There is one caveat, though. The polarity is reversed on these bulbs, so I had to reverse the positive and negative. IIRC some of the sockets ground on the gauge, so these bulbs would not be appropriate for those gauges.

One point of clarification: That description applies to 72 through 78 Z cars. The 70 and 71 are a little different. The headlight switch in those is not on the positive side of the circuit. It completes the ground between the high/low beam switch and chassis. There is no switch on the positive side of the circuit in those cars.

You aren't following it back to the high/low beam switch. That switch will connect either the RB or RW wire to ground. I have three comments on that diagram. 1. I would reverse the 30 and 87 pins. Bring the 12 VDC from the battery to the 87 pin. Most relays you find today are SPDT. That means there is a normally closed contact designated as 87a. When the coil is de-energized, 30 and 87a are connected. If the 87a comes into contact with ground, you'll blow the fuse. If you bring in 12 VDC to the 87 pin, it is just an open circuit when the coil is de-energized. 2. If you use this design, I would suggest a 12AWG wire for the wires going to the 87 and 30 pins. Match up the 12 AWG wire with a 20A fuse. 3. This is the way to wire it if you are considering LED headlights. Otherwise, it may be easier to go with Dave Irwin's design that you can purchase from MSA.

See, he beat me to it.

You have to get the switch knob off, and then you can loosen the ring that holds it on. Be careful. There are parts you can lose. Disconnecting isn't too bad. The challenging part IIRC is getting the optical fiber back in place for the light.

Excellent information. We can work with this. I'll take a look at the wiring diagrams and see if I can give you some more to look for. That is unless BeerManPete doesn't beat me to it.

Unfortunately that's too far for me.

What is the current rating on the fan? That will determine the wire size. The wire size will determine the fuse size. You will want a thermostatic switch for the fan. Wire an SPST relay to the ignition circuit. Pole 85 gets the 12VDC+. Pole 86 goes to ground. Pole 87 gets power from the battery (Put an inline fuse between the battery and the relay close to the battery.), and pole 30 goes to the positive on the fan. The negative side of the fan gets wired to the thermostatic switch, and the other side of the switch goes to ground.

There are plenty of parts links on my blog. Courtesy Nissan has been pretty good to me over the years.

Use resistance to test. Don't trust the beeping. Let's think about why fuses blow. They blow because they have too much current flowing through them for the timeframe they are designed for. The fuse blows to protect the wiring from burning up. Why was there too much current? Refer to Ohm's Law. I (current) = V (voltage) divided by R (resistance). Voltage is roughly constant at around 12 volts, give or take a couple of volts. For a 10A fuse, if the resistance on the circuit drops below 1.2 Ohms, you are getting to the limits of the fuse. (This is why I look at resistance and not continuity.) Beware of autoranging meters, too. All of the sudden the scale could change from Ohms to milliOhms. So, what causes the low resistance? Of course, the obvious is a dead short. Corrosion in bulb sockets can bridge the gap between positive and negative. Also, a relay coil's insulation could break down, bypassing windings and dropping the resistance. The ignition coil could fail in a similar manner. Abrasion in insulation could allow a small area to come into contact with the chassis ground. So, let's work on the diagnostics. (By the way, I spent about two hours today tracking down a short in control wiring for some electrical gear. Even with experience, it can take time.) Can you post pictures of the fuse and wiring in question? I'm tired right now and can't picture it in my mind. I especially want to see where the fuse is. Are you talking about the one in the fusebox? Look for any wiring that may not be factory. Look for splices, electrical tape, etc. Post pictures of those anomalies, and give a description of where you find them in the harness. Maybe Saturday, I can finally look at the wiring diagrams and give you some other points for testing. I hope this helps.

What part of Atlanta?

I believe Dorman 611-254 lug nuts or 611-174 lug nuts. If you need the studs, look for 12mm x 12.5, though I'm not sure of the length.

If you had of posted this a couple of weeks ago, I would have tried to help you when I was in LA.

Ztherapy Rockauto Rockauto Courtesyparts.com (get the part number from carpartsmanual.com) Amazon Blackdragon What part of the door locks? You'll probably have to go to ZCarSource or ZSpecialties ZSpecialties ZCarSource or ZSpecialties Courtesyparts.com (get the part number from carpartsmanual.com) Don't forget the O-ring gasket and locking ring. MSA (zcarparts.com) ZCarSource or ZSpecialties

My last purchase from SuperbrightLEDs included some of these: 1157 LED Bulb - Dual Intensity 1 x 3 Watt High Power LED w/ Reflector Lens | S series | Specialty & Automotive | Universal LED Bulb Finder | Super Bright LEDs They are rated at 105 lumens. I felt they were reasonably priced, and they seem to provide good light. For the single element sockets, a bulb like this: 1156 LED Bulb - Single Intensity 1 x 3 Watt High Power LED w/ Reflector Lens | S series | Specialty & Automotive | Universal LED Bulb Finder | Super Bright LEDs may work well. They are 100 lumens I think those bulbs could be too tall for the side markers, though. Mind you, light output is proportional to voltage. Buying and installing the harness upgrades that Dave Irwin mentioned earlier can improve light output.

Why are you worried about having them too bright? What is too bright?

Hazard Switch ? Brake Light ? Turn Signal Circuit Analysis | Fiddling With Z Cars If it's two out of three bulbs on the right, it's likely to be grounding issues. You can unplug the connector on the light and check the wiring harness to ground. Use the drawing in the link above to find the ground wire. I see that I need to revise it to include the turn signal indicators in the tach. The socket for the right turn signal indicator may not be seated properly.

I think he's talking about the wipers parking in the up position.

So did you sell off your collection of Celicas?

Here's a link to the file if you want it. http://xenons30.com/files/1973%20240z%201974%20260z%20fuel%20system%20modifications.pdf

Nothing. It wasn't a Nissan design.

I used them in the tach, clock, and ammeter/fuel gauge so far. I've been too lazy to change out the others. I'd have to search my garage for the others. Unfortunately I won't be able to do that for a couple of days.

SuperbrightLEDs.com has a nice selection of BA9 bulbs. They also have dimensions for the bulbs to make sure they fit. I put some in my 260Z and was pleased with the results.

The yellow wire is also the power for one of the coils for the electric fuel pump. Leaving that relay in will cause a battery drain if you go to an internally regulated alternator.

Send a PM to Zs-ondabrain, aka Dave Irwin. He might have a good hazard switch. I know he wouldn't sell you a bad one. They can also be cleaned up. This is what I did with an early style hazard switch: Early Hazard Switch | Fiddling With Z Cars