Hello all, this is a great site and while I have lurked before this is my first post. Anyway, trying to help out a family friend with a problem, seems to be a quite a few knowledgeable people judging by the intelligent and accurate responses, so here goes.
Here are the specifics. 2000 4.6 HSE. Everything seemed OK and then one morning -no start. I went to check it out and the battery showed only 4.9 V and looked a bit old. I know these vehicles need a good strong battery so I replaced the battery. All of the electrical functions seem to operate fine, and I checked all the fuses and they seemed OK. So I went ahead and checked to see if the starter was capable of cranking the motor(jumped the terminals). Starter worked fine. With the key in the ignition switch in the "run" position, the vehicle will not start when the starter is jumped- but I suppose that might be the way this vehicle is set up? Anyway, I had a hunch that this vehicle may be experienciing some sort of anti-theft "lock-out" so I took a peek around. Under the dash on the lower left it appeared that this vehicle had some sort of generic alarm installed(had a generic valet toggle and interrupt button) so I removed the under dash covering and found a mass of wiring that did not appear factory. There was a harness that looked like it might have been plugged into a box, but the box was gone. There was another smaller black box that had two connectors - one going back to this mystery harness, and the other snaked up to the ignition cylinder and made a loop around it. Looked like some sort of exciter ring? This struck me as a bit odd, but Ihave always had problems with non factory alarms and remote starters crapping out so I then figured it might be best to disconnect what remained of this system and try to restore the original wiring integrity. I carefully removed the aftermarket harness making sure that all of what looked like the original wiring remained intact. The only wiring still left attached to the mystery harness runs through the door harness on the drivers side and I haven't pulled the panel off to see where it is connected to. Still no luck at this point.
The only thing I hear when the ignition is turned to the start position is a faint click which appears to come from the BECM. Nothing else happens.
Question now is, where do I go from here? Could that other small black box that I removed be a necessary component(it did NOT look factory-but the connector with the loop of wire around the key switch has me scratching my head.. I did find while searching the archives some folks that have experienced roblems with the computer going into a theft mode and requiring a lock procedure to reset the computer. Do I try an EKA 1515 procedure with the key? Is it at a point where the BECM will need to be repaired/replaced? Is there anything else I can do before telling these folks to take it to the dealer?
Sorry for the rambling on-just want to give as much info as possible. Any help that can be offered would be greatly appreciated.