My 99 F-150 Lariat won't start. It starts if I jump the start solonoid. I think it might be the transmission range sensor. I have no trouble codes. Can anybody tell me how to check the range sensor? My wife is going to laugh if I have to call the hook. Thanks

 

It was pretty common for the starter relay (what you are calling the solenoid) to be bad on the early F150 of that generation. Get a test lamp and ground it, and put the test end on the small wire going to the relay, turn the switch to start and see if that wire gets 12 volts while the key is in start. If it does then the relay needs to be replaced. If you get no voltage or low voltage when you key up then test the rest of the starting circuit. Im willing to bet it is the start relay unless you have a security system screwing up the works or remote start system, or if you have a windshield leak causing the fusebox to fill with water.

 

I know it is not the starter relay. I got no juice getting there. Anybody got a pinout of the transmission range sensor?

 

Dark Green/orange at pin 10 on TR sensor comes from fuse 21. Tan/Red from pin 12 goes to starter relay.

 

Might check fuse 21 for blown first. Another common problem is the harness dropping on the exhaust manifold on the RH side and burning through, shorting fuse 21.

 

Thanks all. The problem turned out to be the starter relay. I didn't think I had one as there is a solonoid on the starter. I learned a lot in the last couple of days. Thanks again.

 

So where is the starter relay? Is it in the engine compartment fuse box, or somewhere else?

 

Under the black plastic cover on the firewall.

Follow the positive battery cable.

Steve