I have a 97 LD F250 that I have been having some issues with. There is an intermittent starting problem where you turn the key and it acts like the starter is not working. I checked the power at the solenoid on the firewall next to the 175 Amp Fuses and I was getting 12 volts on the right side and nothing on the left.

Question 1.... Is there always supposed to be 12 volts on both sides of the solenoid? I jumped the solenoid and it kicked over so I then checked the voltage again and I had 12 volts on both sides? Then it started.

I was told that it was a grounding problem so I took all the grounds on the truck including the small ground wires attached to the firewall and I cleaned them all and replaced them. This leads me to Question 2 because I am not getting anything between the posts for power on the 175 amp fuses.

Question 2.... When I was checking for power I tried to check the 175 Amp fuses and if i go from the left post to the right on both fuses, there is no power there. But when I put the positive test wire on the left and right posts and the negative test wire to the negative on the battery I get 12 volts from all 4 posts.

How do these 175's work and why are they there. This is my first time ever seeing fuses this big on a vehicle so I was wondering if they worked differently than a "normal" fuse like a 20 amp did?

Now I sometimes forget to put my windows up when I shut off my truck and I turn the key to run and the windows do not go back up. I turn on the truck and they go up fine.

I am going to try to attach a picture so hopefully someone can make some sense out of what I am trying to explain.... Wish me luck

 

Don't measure "across" the fuse's terminals. As long as the fuse is good, you'll measure zero volts across it. Make all voltage readings with the black meter lead at ground (battery negative) unless instructed otherwise.

They're simply high-amperage fuses intended to protect the circuits that supply or draw the largest amounts of current: The starter and the alternator.

When checking the starter relay, the "right" terminal, as viewed in the photo is always HOT. The left terminal should be hot only when the key is in the START position (which applies battery power to the small coil terminal on the relay to energize the relay).

 

I once had a problem similar to yours which I cured by detached the big cables on the starter & its solenoid, cleaning all the contacts & reassembling everything. Lots of dirt & corrosion down there as the years go by. Not nearly as much in the engine compartment.