1990 YJ +B relay chattering

[eamedic]

1990 YJ with 2.5. Won't start (initially this was intermittent). Fuel pump works if I supply power to it, have fuel to TBI and I get spark when it cranks. The relays check out. When key is on the +B relay chatters. It is controlled by the ecu correct? Any ideas? And where is the ecu located? (I'm almost afraid to ask)

 

[LGR]

Either behind the glove box(have fun), or in the engine compartment driver side. I'm leaning more on the glove box side though.

 

[patyj]

check crank sensor