got a 87 honda accord lx 2.0 2bb with 130,000 on it. the temp gauge isnt working . ive flushed system and at one point gauge worked for a second and i had heat. so i flushed out radiator with water . replaced temp sensor a couple days ago . gauage would go up a little i would get heat and it would drop and no heat . so today i replaced thermostat cause the one in it went bad . plus replaced fan switch too . all fuses and relays are good . fan worked once. im at a loss any help would be greatly appreciated

 

This is the integra section...
I can pretend your car is an integra and tell you that there are two coolant temp sensors (one fore the gauge and one for the ecu), but that might not be true for your not an integra car.
Maybe your gauge cluster is bad or you have a bad ground. I'm not sure, delete this post and post in the right section and maybe you'll get a better answer.