Hi,

I have an 89 Honda Civic that won't start when the engine is warm. It starts fine when I get up in the morning or if the car is cold. But after driving and I need to stop to get gas, sometimes it won't start. There's plenty of battery power and the starter is fine, it just won't start. I have to wait about 5 minutes and it'll start again. Sounds like a relay problem but I am not sure where it's located.

Thank you.

Yes, you need to replace the main relay. It's located just above the fuse box.

. Remove the coin box for a better view.
. With a 10 mm socket or wrench, reach inside and at the top of the relay you will feel a bolt.
. Unfasten the bolt.

If you cannot unfasten the bolt, you may alternatively:

Remove the internal relay assembly. Press your thumb against the right relay case wall; then, pull the right side out. Press again on the left relay case wall and pull the rest of the relay out. The main relay is live, so you should disconnect the car battery; otherwise, you may accidentally short out the relay or other nearby parts. The symptom of a short is when your car won't start after you replace the main relay. Pull the relay down and unplug the connector, by squeezing the lock and separating the connector from the relay.