1990 740 GL Auxillery Relay Wires

Been having stalling problems intermittently for the past 12 years. While driving the car would all of a sudden shut off. This only occurred once in a great while, so I did not think much of it. Loose wire or something. I searched, checked fuses.

Eight years ago, the in-tank fuel pump quit. I replaced it and didn’t have a problem with the car shutting off for several months/years. Once in a great while my wife would report the strange occurrence.

Then two years ago, the car shut off while I was driving and would not start. Next day it started right up. I replaced the fuel pump relay. No issues with it shutting off until the past few months. Now it happens every couple of weeks or so.

The car shut off while I was driving, all the lights illuminated on the dash. Stopped, put the car in park, took the key out, and then reinserted it and the car started fine.

Spoke to the Volvo parts dealer in Texas and they recommend that I replace the Auxiliary relay, as this is part of the fuel system.

I have the new relay, but today when I disconnected the wire harness the individual wire insulators fell apart, (tan colored waxy material around each of the four wires) and the wires came out. Now I need to know which ones go where.

Please assist if possible ASAP. I need to fix the wife's car ASAP.

Tks,
Russell

I forgot to add one thing; the relay in question is mounted in the engine compartment, forward of the right shock strut area. There are two relays, the Aux relay is the one inboard toward the engine.

The wires that I have are solid Red, solid Black, Green with Red stripe, and Red with Yellow stripe.


Tks,
Russell

Sorry, but got one wire wrong.

Here's the wire colors as I wrote them down this time.

The wires that I have are solid Red, solid Black, Green with Yellow stripe, and Green with Red stripe.


Tks,
Russell

[Peter Milnes]

Hi Russell, the relay you refer to should be the Radio Suppression relay and is the power feed relay for the fuel injectors. Wiring as follows:- Red wire goes to pin 4, Black wire goes to pin 1, Green(Blue?)/Yellow wire goes to pin 2 and Green/Red goes to pin 3. Same colours are used whether LH 2.4 or Rex/Regina or Motronic (760) sytem is used. Blue/Yellow is the colour for the pin 2 wire according to the Green book.

All the best, Peter.

Peter,

Thanks for taking the time to assist me with this challenging problem.

Best wishes,
Russell