Hello. I have been trying to diagnose my wife's non-start condition. The car died completely shortly after being started in a parking lot. The engine cranks but never catches.

I am following (to the best of my ability) the checklist in the RNG Volvo Problem Solver, I am not getting a lit test lamp at terminal 1 of the coil unless the white wire there is unplugged. If I reattach the wire at coil terminal 1 and then disconnect the ignition control unit, I do get a lit test lamp. In this case, the Problem Solver says the control unit is either grounded-out or bad.

So my question is how to determine which it is? Is there a procedure for testing the control unit? This is a box that is mounted at the wiper washer reservoir. It has no vacuum attachment - just a connector at the bottom which spilts going two ways. One way seems to go, with the white wire, back to the coil. The other way goes to a connector closer to the engine (not sure where that goes but the diagram indicates to the distributor). I would hate to replace it unless this is really needed.

Thanks for any pointers!