Alternator and engine temperature guage.

I just installed a new engine. Everything is working great except my alternator and the temp guage on my dash...
I charged the battery's and tested them they are good. Tested the alternator and the battery's while the engine was running and they are not charging. replaced alternator. Still not charging battery's are going down slowly as the engine is ran, but holding fairly well.
The engine temperature guage on the dash is not moving at all. Even after 20min of driving in my parking lot. I have checked all fuses and they are all good.
I am really at a loss of what to check next and I need this truck for Monday. What do these 2 problems have in common? Do they intersect somewhere that could short out causing neither to work?
Please help!

Sent from my C811 4G using Tapatalk

I'm getting 3.73 v at the number 6fuse under the hood and 9sumthing v at fuse number 29 under the steering wheel...
I guess I'll try locating the fusible link?

Sent from my C811 4G using Tapatalk

Talked to a diesel mechanic I know and he said that the wire connected to the back of the alternator is supposed to have 12v from the battery to engage it?
If not doesn't he said to trace it back until I can find 12v. Does that sound right to anyone? I thought that cable sent power from the alternator out not in from the battery's? I hate electrical stuff. Just because I don't know enough about it.

Sent from my C811 4G using Tapatalk

See my answer in your other thread.

Figured it out. Traced it back to the starter selenoid. I had the wiring backwards! I'm an idiot.
Thanks for the advice.
Trucks running good now.

Sent from my C811 4G using Tapatalk

I did the paperclip in the temp sender pigtail and got nothing.
Believe that means something is amiss in the wiring. If I'm wrong key me know. Thanks.

Sent from my E6782 using Tapatalk

What year truck and what year harness on the engine?

Both 2001. Guess I didn't see this when you posted.

2001 F-250 cclb
7.3l 4x4
forged rods,
ebpv, muffler, dp80hp dd.

I'm going to be digging into the wiring a bit for some glow plug problems I'm having. I'll probably do some more checking on the water temp problem too.

2001 F-250 cclb
7.3l 4x4
forged rods,
ebpv, muffler, dp80hp dd.

When I bought my truck, the temp gauge didn't work. Replaced sensors etc with no luck. When I installed my injectors, I noticed a bent pin in the main harness connector. Straightened it out and bam, the gauge has worked since. Worth a look...