1988 Accord temp gage and fan problem

Rebuilding my 1988 Honda Accord LXI. Purchased it new.

I'm having problems with the temp gage and not sure the cooling fans are engaging properly. The temp gage recently started to jump to the top when the vehicle was cold. I reset the ECU and the gage went halfway when the engine was cold. In both cases the gage did move up as the engi9ne warmed but the reading is obviously suspect. I did a resistance test on the sending unit and a test on the gage and they appear to be fine.

I monitored the coolant temp at the radiator, don't have a thermal reader available a temp probe was my only option, and the main cooling fan did not engage at 200 dez. I haven't checked the switches yet but the fans both work.

Two other items of note. The alternator went bad and was replaced by a Honda remanufactured part purchased from the dealer. My daughter also got a jump from her boyfriend when the battery died about 18 months ago. He inadvertently touched the jumper cables together long enough for the cooling fans to run (engine was cold so they shouldn't have started). After turning the car off and restarting the problem appeared to be reset and there didn't appear to be a problem until recently. These problems actually didn't appear until after the alternator was replaced but that may be coincidence.

Any help is greatly appreciated.

The first thing I'd do is check for a broken thermostat. The engine will overheat internally and the radiator will stay cool.

Unplug the single wire sensor thats connected to the thermostat housing. It has a black hood over the connector. I was having the same problem. Let me know if it works.