replaced temp sensor,elbow and lower hose.anti freeze drained from radiator,filled with anti freeze, purged system...but temp gauge stayed on cold,ran for over an hour, temp gauge never moved..Had replaced thermistate 3 months ago cab has plenty of heat...what did I do wrong.

 

The system might need to be reset. Pull the negative then the positive cables off the battery. Let sit for about 15 minutes or longer. Put cables on battery in reverse of the way you took them off. Some people say then let your truck warm up for 5 minutes. Turn the heat on for three minutes. Do some stop and go driveing at the normal speed. Come to a complete stop every time for 15 minutes. Do some highway driving at 60MPH with cruise on the entire time for 15 minutes. Then when you get off the highway choose an exit with a long enough road to cost to a stop. Or just sit there and see if you get the heat needle to move. I did the top stuff once. Never gained much from it. I have unplugged the battery then when I plug it back in did nothing. I think the computer might not know that those parts are fixed. Thats why you get the bennifit from your work but the meter is still not working. Just an idea. Hope I helped.

Jim

 

If you replaced the Temp SENSOR then that was the wrong part.

Temp gauge on dash uses the Temp SENDER

SENSOR is only for the computer

SENDER is only for the dashboard gauge

SENDER will have a Red/white stripe wire and Black/white stripe wire in 2000

To test if SENDER or wire and gauge are the issue remove the SENDER'S connector
Use a Jumper wire and connect senders Red wire to Black wire, so short it out
Turn on the key and watch the temp gauge, it should go all the way up to HOT
If it does then wire and gauge are OK, sender is bad

If gauge doesn't move then wire or gauge issue.
Try using jumper wire from Red wire to a good ground, then turn on key, to see if gauge goes to HOT, if so then Black/white stripe wire is bad, it is suppose to be a Ground.