vistacruiser1971

I have a 1992 Silhouette with 300,000 miles and for a couple of years there has been a slow start condition once in a while. When the car quit starting I replaced the starter and solenoid with a good rebuilt unit. The car goes back to starting but slowly. The cranking speed is fine but sometimes you hold the key to the start position and a second or two later it will start cranking just fine and starts. I replaced the steering column ignition switch to see if this helps. However, not the case. Recently it took 20 minutes of no crank at all before the van would start. This is a pain so I hooked up a wire from the solenoid for testing. When the van would not start I left the key on and touched the test wire to the battery and got a nice start right away. Looking over the GM wiring diagram it seems the start wire goes thru the ABS relay to my surprise. I can't get a new relay at the local GM dealer. The aftermarket ones don't have the same part number and wonder if they are correct. Counter person gave me two relays and said either would work.
Really? Does the factory relay " P&B VF4-75F21-Z01 G.M. ABS VI 12088595" wear out? become intermittent? There are used ones on ebay but their condition of course is unknown. Your experience on this issue would be appreciated. Thank you, Trent in Los Angeles.

oldcutlass

Not familiar with your car, is there another relay in the control box thats the same that you can just swap positions? I'm also wondering if you have a neutral safety switch in the circuit? When you have the no start condition get a multimeter out and check to see where the voltage disappears in the circuit.

vistacruiser1971

No other relays to swap. There is a neutral safety switch which could be checked. Never had either a neutral safety switch or relay go bad. Has anyone seen problems with either of these electronics? Thank you for your reply and suggestion. Trent in Los Angeles

vistacruiser1971

Gone are the days of the familiar neutral safety switch in the shape of a 1/4 moon above the steering column. This FWD van has a "Transaxle Position" switch which I am not sure how to test. There is a set of wires coming from the transaxle where the lever attaches from the steering column allowing the driver to change transaxle positions. Thank you for your help. Trent in Los Angeles

m371961

I am not familiar with this setup at all, but curious if the vehicle is one where the brake pedal must be pressed to start, and this is why it runs through the ABS system. Can you read the relay diagram and bypass the contacts for the start circuit?
Rock auto lists a ABS warning light relay and a electronic brake control relay

vistacruiser1971

Part of the reason I like this car is that is was made before many added features which makes things even harder to service. The van does not require the brake pedal to be pressed before the van will start. Reluctant to bypass the relay circuit because of a possible fire if that circuit is not designed to be powered "on" at all times. Because the problem is intermittent, this wire might be needed long term if the relay is the problem. I hope to find out if relays can wear out and how to test them.

The rock auto part for the electronic brake control listing shows:

ACDELCO 12088595 GM Original Equipment Info
LOCATED IN SHOCK TOWER CONVENIENCE CTR

This is the same part number as the relay I have removed. It was located on the shock tower and there is only one relay on the shock tower. It has "ABS VI" printed on it so I think the ABS relay and the electronic brake control relay is one in the same relay. The AC Delco part is out of stock and only aftermarket relays are offered similar to my local part store.

I really appreciate your help. Trent in Los Angeles

m371961

If one of the others was the standard Motor Products one, they have a good rep. If you can remove the cover of the relay you can see the operation of the coil closing the contacts. Otherwise you have to probe into the wires and see. It is a simple thing, just a positive and ground that activates the coil that then closes and opens contacts to send or remove voltage from a source to a device.
But, it can still be the neutral switch. the only way to tell is to follow the wiring from start switch to starter.