260 a/c relay

[anthony_c]

the a/c compressor relay for a 260z is no longer available from anyone. anywhere.

it was suggested by a mechanic that i could substitute in any 3-blade relay provided it was rated for the correct amperage. he added that most old horn relays would probably work.

anyone have any experience or thoughts on this?

thanks,

tony,

richmond, va

[SteveJ]

The mechanic is correct that another relay could be substituted provided it has the correct rating. Is this a stock or aftermarket A/C system? Can you post a picture of the relay and the socket?

[anthony_c]

thanks steve.

this is a stock ac system but the original relay is long gone. according to Courtesy Nissan the original part number is 25230-89954.

page AC-36 of the fsm indicates that i need a three pin relay, but it doesnt tell me much more than that.

the harness connector is a round rubber plug with three bullet style connectors embedded in it.

Edited July 13, 2013 by awconroy

[SteveJ]

Actually, the drawing tells you a lot. You just don't understand the language. Don't worry. I speak electrical.

You can replace the missing relay with a standard automotive relay. You will just need to replace the connector in your electrical harness. A relay such as this has contacts with a high enough rating to work for you. You will need to splice a relay base onto your wiring harness.

First, figure out which blue wire is on the ACC fuse and which is on the A1 fuse. These should be in the fuse box shown on page AC-35. The blue wire on the ACC fuse goes to the 85 terminal on the relay. You need to run a wire from the 86 terminal to ground. The blue wire from the A1 fuse would go to the 87 terminal on the relay. The green wire goes to the 30 terminal on the relay.

If you are not comfortable with doing your own electrical work, contact Guy, aka Diseazed on this board. He lives in the Richmond area and could probably point you to a good electrical person.

For more information on relays, I wrote a brief primer. Relays Simplified | Fiddling With Z Cars

Edited July 13, 2013 by SteveJ
Made a correction

[anthony_c]

two blue wires? by any chance are you looking at "RELAY - POWER" instead of "RELAY - COMPRESSOR"?

[SteveJ]

Yes, my bad. For the relay I linked, the green wire would go to both the 85 and 87 pins. The yellow goes to 86 and the blue goes to 30. Now all is right with the force.

[anthony_c]

pardon me as i drag you through auto electrics 101...

if i am reading your instructions and the diagram correctly, it dont *think* i need terminal 87a included on an spdt relay. would a spst similar to this work as well, or am i overlooking something?

on a vaguely related note, i read your article and the paragraph on parking lights describes my task perfectly. while fumbling through the harness i noticed that GB wire leading up the combination switch was damned hot after only a few minutes of use. fwiw it cooled down significantly after spreading the wires out to let some air flow in.

[SteveJ]

You are correct. You don't need the 87a terminal. I usually remove the wire from the base if that is the case. It is a challenge to find SPST relays. I'm not sure why.

I'm not surprised about the green/black wire being hot. the connector had melted on my headlight switch from that. Check the sockets in the parking lights, especially the ones on the sides. You are likely to find some corrosion in them. Cleaning out corrosion can prevent it from completing a relatively low resistance path. Dave Irwin's relay harness (sold through Motorsport Auto) can protect your switch. As I have documented elsewhere here, LED bulbs greatly reduced the load on the circuit, too.

[anthony_c]

Steve, this process never really ends, does it?

i started several weeks ago with turn signals, gauges, and few other items that weren't working and chased that goose for a week until i found the short. i was still left with a 1.25 volt drop at the fuse so i sanded and cleaned every terminal i could find in the path, had the alternator tested twice, replaced the voltage regulator just in case, and cut and re-terminated all of my ground wires for good measure. i wouldn't call the situation fully resolved yet, but with a full charge on the battery i can just barely hit 12v at the fuse again. Close enough.

while working on the original issue i found a broken lead on the reverse light switch, another broken lead on the a/c pressure switch, and several issues with the a/c relay wiring. re-work of the relay is in progress, but its not looking good for the pressure switch. oem and aftermarket switches are n/a, and the wire was broken right at the switch itself so i don't think there's any hope for repairing it. 4Seasons makes a new receiver (part number 33286) that looks like a drop in replacement, unfortunately, no one seems to have a pressure switch for that one either. at this rate the car wont be ready 'til late fall, so one could argue that i have another year before i need to worry about the a/c.

the other immediate concern is the issue of the little green and blue wire in the steering column. the front, rear, and side marker bulb sockets were all reasonably free of corrosion, but the connectors behind them are all pretty crusty. with all of the aforementioned bulbs out of their sockets i measured a 1.25v drop between the connector under the passenger seat and the right rear side marker. after a light sanding and cleaning the voltage increased 0.5v. Repeat that process for every spade, bullet, and pin and just pulling new wires sounds like a reasonable option.

As Jeremy Clarkson would say, "what could possibly go wrong?".

[SteveJ]

Yes, 40 year old wires can be fragile.

For the parking light circuit, you can reduce the current loading by switching bulbs over to LEDs. Here is a thread with more information: http://www.classiczcars.com/forums/electrical-s30/40600-sold-leds.html