1998 pontiac grand am tach wire location

Like the 98 cavalier...ther should be a BIG harness that goes across the transaxle on the drivers side. Its under the air intake tube. Inside that harness you'll find ALOT of white wires. 1 of them is the tach. Get your meter out and test em till you find the one you need. I stoled this from the bulldog site. see #2 This might KINDA help...?

NOTE *1 the LIGHT GREEN/ BLACK (-) is for the DRIVERS DOOR this wire is located in the DRIVERS KICK PANEL. The PASSENGER DOOR wire is a LIGHT BLUE (-) in the PASSENGERS KICK PANEL, when connecting to an ALARM SYSTEM, use both DOOR TRIGGER wires and DIODE ISOLATE. to connect, See

DAIGRAM NOTE *2 the TACH wire on the 4 Cylinder engine, is a WHITE wire in the 16-Pin harness, top Right side of the engine, and on the V-6engine, the tach wire is a PURPLE / WHITE at the Coil Pack.

PS, your picture doesn't help you....or me.