My 90 Honda civic heat won't work. I think it is the blower motor but not sure because it could also be the fan switch but again not sure. Any suggestion on how to test those parts would be great.
Thanks.:confused:

Begin by checking all under-hood and under-dash fuses with a test light or multimeter. In the under-hood fuse/relay box, there is a 30 A fuse and a relay that go to the heater. Check those out, for sure.

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-honda-civics-46563-3.html#post252145