Checking the electrical output/input of parts. How do I know they are working right?

[MechanicallyInclined]

I have a volt/amp meter and am trying to find out if a particular wire has a short in it before replacing part after part til a problem is cured. I have seen wiring diagrams for my 94 6.5td.

In order to find a short in a wire to...let's say...the fuel shutoff solenoid....how would I know what voltage or amps that the solenoid should read?

Does someone have a list of what the parts should read? (e.g. fuel shutoff solenoid, pmd, lift pump, batteries, ops, etc.)? And whether the engine has to be in off, on, or start position?

I'd hate to have to replace parts when a short may just be the cause. :smile5:

 

[buddy]

The best thing would be to purchase the GM factory 1994 diesel supplement. It has everything you are asking about. I have it, its great.

THIS POST shows the supplement, red and white service manual

 

[dms4x4]

Since the system is 12 volts, I'm guessing most devices will be rated for that voltage, and you would expect to see 12-13 volts at the power terminal. The amp load is going to be a little tougher to determine, as well as measure, and you won't know if your reading is good or not without detailed information on your part.

Buddy's suggestion to get the manual sounds good. I'd like to have one for my '93. Where do you buy it, and how much should it cost? I got a manual off ebay with a pciture of a truck on the cover. The seller advertises it as the diesel "bible". In reality, it's a GM training manual. I paid $55 for it, and it has some good stuff in it so I'm not dissatisfied, but it's not a service manual with complete wiring diagrams like I anticipated.

Keep in mind, the wiring diagram will typically be drawn in a de-energized position. Further, the cranking configuration of a relay may be different than the run state, and what with all the controllers, etc, it's going to be hard to put a meter on something and make a diagnosis.

Are you familiar with the codes, and how to get them? The auto zone guy showed me how to take a metal clip, stick it in a port, I believe under the dash, and count the flashes. I believe the later models require some type of reader. Maybe somebody else can shed some light on this. In any case, better to make a good diagnosis and an educated guess before chunking out money for expensive parts. Good luck and be sure to tell us what you found out.