The lead from the 87a contact on the Fuel Pump Relay goes to a connector called the Fuel Pump Prime Connector. This connector is not used on my Suburban either. The reason it's hot is because the relay makes a connection from the A3 contact to the 87a contact when it is not energized. Since you hot wired the A3 contact (grey wire on the underside of the fuse box) this makes the 87a contact hot also.
The relay gets energized for two seconds each time the ignition is turned on or off and thereafter when the engine starts. This is controlled by the Vehical Control Module (VCM) Pin one of connector C4 (top right corner) on the VCM has a green wire with a white stripe that energizes the 85 contact on the relay, which closes the relay and connects the 87 contact (+12 always hot) to the A3 contact. If you are not getting two seconds of +12V on this lead then I would inpect the connector/wire etc. You can unplug the C4 connector and pop it open to inspect the contacts. You should disconnect the battery first. If you are not getting +12V on the 87 contact of the relay then check the fuse. If everthing checks out, I would replace the relay with an OEM relay from the dealer.
Wednesday, October 10th, 2007 AT 5:41 PM