1994 Ford Thunderbird

What are the symptoms? If the engine doesn't crank, does the solenoid / relay click?

caradiodoc

Yes, I hear a click, but the starter doesn't turn.

Check the connections on the two large nuts on the starter relay. It sits near the battery on the inner fender, and is black, about 2" around. You can follow the red positive battery cable to it. It is real common for those nuts to work loose because they are just soft copper. That's what should be clicking when you turn the ignition switch.

If the nuts are tight, measure for voltage on both of them when a helper turns the ignition switch to "crank". A test light should be bright, or a voltmeter should read at least around 10 volts.

caradiodoc

I do not know if you refer to the 94 Thunderbird relay. I know that relay was on the inner fender on the early models, but in my car there are two red cables coming from the batter terminal, one is going to the fuse box on the inner fender, the other is going under the engine, probably right to the starter solenoid. I have to look closer where that relay is located. Today I had that starting problem again and I tried to overpass the safety neutral switch by starting from neutral shifter position, it did not work either.

If you are familiar with the old round solenoid that was used on the older models, that is the same part that was used as the starter relay when the solenoid was on the starter. My guess is it didn't make sense for Ford to buy millions of relays if they had a whole pile of solenoids already in stock that needed to be used up. The way to tell is to look at the wires on the two large terminals. Either way, you should see a large red battery cable going to it. If the second terminal has a fat cable going to the starter, they are using it as the solenoid. On the newer models, the second wire will be real small. It is being used as a relay to operate the solenoid on the starter. It's the same part, just serving a different function.

caradiodoc