Temp Gauge Sender issues

SlantedMark4 said
My temp gauge didn't work, so I have replaced the dash voltage regulator

PLEASE ANSWER EACH QUESTION...
And watch this video

Did the fuel gauge work at that time?

SlantedMark4 said
but when I started the engine, the temp gauge went up to 250° and back to 0° when the engine was warmed up.

Was the engine cold at that time?
Did you allow the engine to warm up to normal operating temp as it went down to 0?

Is 250 pegged to the right?

If so how long did it stay there?

Are we talking deg F or deg C?

SlantedMark4 said
I've thought the temp sender was bad, so I have replaced this one aswell

Give us the part number of the sender you had and the replacement

SlantedMark4 said
Now, the temp gauge doesn't work at all while everything else works fine.

Define everything else.

Only the fuel gauge and if so equipped an oil gauge ( not idiot light type oil light) have anything in common with the temp gauge

SlantedMark4 said
The temp gauge has light, so I don't think it's a cluster problem but either the sender or the thermostat.

The lighting in the cluster has little to do with this. If the ground to the cluster was missing the lights would not light and the temp and gas and if so equipped the oil gauges would peg and eventually burn out.

SlantedMark4 said
The thing is, I have replaced the thermostat 2 years ago..

The thermostat does not have anything to do with this. Check the engine temp at the base of the thermostat housing or at the base of the temp sender with a infrared temp gun or other temp probe that can make good contact.