My B3000 ran beautifully until I changed the water pump. Now I can only crank it by jumping the solenoid. After that, it runs fine, and everything works. There is power at fuse #24 inside the truck when I turn the key to "crank", but no power at the push-on terminal at the solenoid. There is no alarm system. The only wires that were disturbed when I replaced the water pump were the ground terminal at the battery and the wires in front of the water pump, which have all been reconnected. The battery has a full charge, and the terminals are clean and tight. The fuses in the fuse box in the engine compartment are all good, and I cleaned their terminals. I wiggled the gear shifter in park and neutral while turning the key.

 

Is there power at #24 when the key is NOT in the crank position? I'd expect there is. To search the trouble, you have to trace the circuit to see where you lose power.
The neutral safety switch will interrupt the power, and may have failed completely. You can try the 'sweep' test, where you sweep from P to L with the key in the start position. If it cranks then, I'd look at the switch more closely. If not, you can only trace back to the ignition switch to see if power gets out to the safety switch.
You may need an ignition switch or neutral safety switch. The other option is pinched or cut wires leading to the relay. Corrosion can cause problems too. Get the color code on the solenoid and check that color wire on the safety to perform a continuity test of that wire if you get that far.
Water pump must have been coincidence unless you jacked it up and moved or damaged something.
tom

 

Ok, I just did some more checks. The fuse only has power when I turn the key to "crank". I switched relay 6 with another relay. I swept from P to L with the key turned. Nothing. Now what?

 

You say the problem started after you changed the water pump, and had to move some wires to do that. Start at that location, check the wires you moved, make sure you didn't pinch one, and if they weren't all in one connection, make sure they are connected right.

 

solenoid might just be bad it happens sometimes and they are cheap and easy to replace

 

I rechecked all the wires I had disconnected. They were in a cable separate from the ignition wire. There is power at the fuse after the switch. I switched out the relay. I don't believe there is power to the relay, as I didn't hear it click when the switch was turned. There is no alarm system, so there is supposed to be a straight shot from the fuse to the gear selector switch to the relay. I can't get to the gear selector switch in the steering column, but sweeping the gear selector from P to L with the key turned did nothing. There is no power at the push-on terminal of the solenoid when the key is turned.

 

If you apply power to the small terminal on the relay, does it engage and power the starter? If so, your relay is working, and you have a wire or neutral safety switch problem.
I have jumped from the large + terminal on the relay to the small terminal using a screwdriver in the past to test, or to bump the crankshaft while setting ignition timing.
Do that, and report back...

FWIW, most lever position switches are/were mounted further down the steering column so that they were relatively easy to access.
tom

 

I'm sorry. I forgot to say that I had tried that. It cranks when I touch the small terminal with power. Where is the neutral safety switch located?

 

Where is the neutral safety switch located?

As noted:
FWIW, most lever position switches are/were mounted further down the steering column so that they were relatively easy to access.

The neutral safety switch is used to determine the position of the transmission gear select lever. It is to prevent starting the engine with the car in gear. It is also called the MLPS, or Manual Lever Position Sensor, depending on who wrote the book and more likely when. Older name was neutral safety, newer name as noted because it also tells the transmission computer if you are using OD, locking the gears in 1 or 2, or ??? you pick it... What year is your truck?

 

1996 Mazda B3000

 

The neutral switch is called the Digital Transmission Range sensor, and is located on the left side of the transmission at the shift lever. I just looked under the truck, and could only see one connector, the 16 pin one. I didn't see any loose cables.