Thanks for investing your time in my dilemma. Everything about the key works: when you twist it unlocks theft prevention, key turns as it should, but it will not close the starter circuit and make the starter go. Takes several tries before it does. Sometimes it only takes a second try. Sometimes on the second try you have to hold the key in the start position for a second or two before the starter engages and turns the engine over. Sometimes you have to index the shift lever through the gears and back before the key engages the starter, and sometimes you have to index it through the gears several times before it completes the circuit and engages the starter. It always starts, eventually, but it is getting worse.

Which part needs replacing, and how do I fix it? THANKS!

 

Automatic I assume?

START signal goes like this:

Battery(12volts)---fuse9--ignition switch(under steering column)--fuse21---Transmission switch(on transmission)---starter relay(in engine fuse box)---starter motor

Fuses are OK or it wouldn't work at all

First try Turning key on, then shift to Neutral, then try to start engine, if that works then its one of two things
1. The Column shifter is loose so when you put it in PARK is not moving the Transmission switch (DTR sensor) far enough to close contacts for starting
2. DTR(digital transmission range) sensor is bad for Park position

DTR is on drivers side of transmission on the shift Rod, it tells computer what "gear" driver has selected, and it also passes the 12volts from ignition switch to Starter Relay when its in Park or Neutral position


If shifting to Neutral doesn't help then replace the Starter Relay in engine fuse box, its not expensive, if that doesn't help..................

Then you will just need to test for 12volts at fuse 21(cab fuse box) with key in START, to see if ignition switch is OK
Then test at DTR sensor than it has 12v when key is in START, then at Starter Relay with key in START
Then at starter motor with key in START
It could be the starter solenoid(on top of starter motor is failing), longer shot but can happen, usually starter motor fails not the solenoid

 

Thanks Ron for your detailed reply! That's a repair roadmap even I could follow. It's my 96 year old father's truck, so I want to get it fixed asap. He has the magic touch: It starts first or second time for him. Me, I'm indexing the gears, folding the visors down, jiggling the key, every gyration you can think of, and he just sits there and chuckles at me. I SHALL get to the bottom if this. Just not now in this 99 degree heat. Maybe wait a couple of seeks. THANKS!

 

Does this truck have a tilt steering wheel ?

Try it tilted all the way up, then all the way down.

 

No, no tilt. This was an IBM serviceman's truck. IBM orders bare bones fleet trucks, not even cruise. He was obsessive/compulsive about caring for it. I know the IBM salesman who bought it from IBM after they convinced the guy to turn it in for a new one. He didn't want to turn it in! 7000 miles after he was suppose to (150,000) they MADE him, or else. Just an awesome little war horse, my $2400 sacrificial lamb to protect my other rolling stock during adverse driving conditions like black love bug season. More comfortable than my Tacoma. (OMG!!! HE OWNS A...don't say it!...A TACOMA!!!)