Ecu relay and fuel pump relay - mv motor

1

Seems ECU relay’s are out of stock everywhere! Just wondering how special the relay’s are?
From some reading, there was a change in ~'88 in both the ECU relay (old number 321919505) and the ECU (old number 025906022) itself. The later relay’s have 5 pins (extra pin 87A), relay 321909505A and ecu 025906022D
I have a spare I bought some time ago, but is marked as “auxiliary fan relay”, however the part number and circuit match what is needed for the ECU. I just want to confirm they are interchangeable? I’m also wondering if the fuel pump relay (relay 53) would work for the ECU? I know it works for pre '88 vehicles as there is no terminal where pin 87A is.

This is the relay I bought some time ago, but is listed as both ECU and fan (incidentally the fan relay in my van has pin and plug for terminal 87A). So both appear interchangeable.
321 919 505A



some generic ones, I assume as long as the circuit and pin numbers match they would be fully interchangeable


And some people obviously think they are gold plated?

I also have one of these as a spare fuel pump relay, but again I assume as long as a generic relay has the same circuit and pin numbers they are interchangeable


And is usable for earlier ECU relay’s. Just not sure on implications using this for the ECU on later van’s with terminal 87A wired into the harness.

If you do not have one, might be good to source a spare as they could be hard to find if you break down.

Out of interest, a number of articles note the change in '88 was to support a data out pin in the ecu for monitoring. So does not appear to affect operating, and the data out port does not appear to have been used (possibly was in the factory?)

2

I am not 100% sure, but I think that these may be a generic relay. You could just carry a male-male jumper lead to get you home.

3

Good point Phil. That would be an easy fix!
Going through more of my bits and pieces I have tonight, found a few of generic 5 pin relay’s.
The ECU relay, pin 87A seems seems to be an alternate pin to turn the relay on (perhaps for latching?)
image
Where as the generic ones, same pins, same pin numbers, 87A is a NC contact, 87 is a NO contact!!
So not so simple!
image

4

Depending on the location of the pins, the bottom one looks like a generic relay. We used to call those air conditioner relays as they were used in aftermarket ac units. Some relays with 5 pins have 87a connected to 87.