Ground the two wires that come out of the connector on the MAP switch on the passenger fendwall. Turn the IGN Key to ON and see if the two lamps light up on the dash.
If so clean the mounting bracket to fenderwall mount as that supplies the ground to trigger the lights.
The switch can be removed and cleaned with electronic cleaner there are two adjustable mechanical switches inside that can be set and checked with regulated shop air and an ohmeter. One lead to the case and one to each output tab. There are two screws under rubber covers for adjustment.
Also use a gauge and make sure you have boost pressure to the MAP switch itself on that hose.
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