each plug draws 15 amps, this pulls the dash battery volt meter down in to the 9-10volt range during activation, if you do not see that good chance they are not activated, a hole saw to the inner fender well gets to the tough 2 plugs. there is a mod using a fender mount Ford starter solenoid to extend the on times for cold starts using the new ac delco60G plugs on this site someplace the 92/93's need it.
92 chevy CK2500 354K miles. Underdash fuel gauge,teed into injector pump inlet with a needle valve air bleeder. Under dash ammeters on port and starboard glow plug circuits. Under dash oil pressure, and temperature guages. Rebuilt Tranny