You're probably right that the ECU is more sensitive to voltage spikes and that is the real reason the resistor is there but it also prevents arcing across the relay contacts. In any case, the resistor (or diode) provides a low impedance path for the coil current to dissipate. Since the impedance is low, the voltage spike is low as well, since V = IR. This both prevents a voltage spike into the ECU output driver (also low impedance I would assume) and prevents arcing since the voltage across the contacts is limited.The diode or resistor in relays is across the coil to protect the switching circuit (ECU), from high voltage when the magnetic field collapses.
Hey VAGguy, you don't have a spare 373 (28/99) relay do you? I'm happy to pay for one.OP, what is the number on the top of the relay? I can check the ones I have and ship it to you so you have the right one in there...
I tried a new relay but it probably was the wrong type.Did you try a new relay ?
Did the same problem exist with the new relay installed ?
-I popped out the relay and can only see a small length of the blue/grey wire, however it looks like new. I reached under the relay to run my finger along the wire, and noticed that when the wire is touched, the contact that connects to the relay's left-most post (when facing car from front) is VERY loose, wiggles and moves up and down.Check the Blue/Grey wire from the relay to the ECU. Check for an intermittent short to another wire or ground.
Ok, from what I can tell the actual (copper?) socket makes direct contact with the relay when I plug it in. I'll look extra close to make sure there's a good connection between the wire and the socket while I'm doing my multimeter business today.If that wire is loose when the relay is plugged in, it is a problem.
This would indicate a bad wire connection to the socket or a bad connection between the relay and its socket.