hpdude02

Hello, I have a 98 Honda Civic with a blower motor that doesnt work. I have purchased a new motor, replaced the relay, checked the fuses (7.5 relay and 40 motor) and replaced the resistor. Nothing works. When I bypass the relay switch, it will work but a new relay has no effect. Thank you for any guidance you could suggest.

Former User

How are you doing this? Does jumping the relay socket from either terminal 3 or 4 to terminal 1 make the blower run?

hpdude02

yes, I bypass by connecting the terminals (1 to 4?) with a paper clip and no problem. But when I put in the new relay, no luck.

Former User

Test whether jumping 3 to 1 makes the blower run.

Then turn the key to ON(II) and test whether jumping 4 to 1 also makes the blower run.

hpdude02

Thanks for posting the diagram, I couldnt find one. I tried 1 to 3. Also tried 1 to 4 with the ignition to ON but neither worked. Jumping from 2 to 4 works. Accidently tried 3 to 2 and that worked but ended up blowing the 7.5 relay fuse.

Former User

If you think about it, the relay terminal pin out is the mirror image of the relay socket terminal pin out.

Here's the conversion:
(your terminal number ---> actual terminal number)
2 ---> 1
4 ---> 3
3 ---> 4
1 ---> 2

So the 1-3 and 1-4 tests worked. Your tests show that the relay gets voltage from both hood 40A fuse 55 and dash 7.5A fuse 17. It was expected that fuse 17 would be blown in the test because it cannot handle the high amps that the blower pulls.

Your results also suggest that the black ground wire running from terminal 2 in the relay socket is bad. Do you have a multimeter to test continuity to body ground at terminal 2?

Also, do the mode controls in the heater control panel work?

hpdude02

I was able to get hold of a test light. It looks like the ground at terminal 2 is open. When I turn the ignition on, terminal 4 is hot. I know that the alternator went around the time that the blower motor went. The dealer installed a new alternator.

The mode contols appear to be working.

Former User

How are you using a test light to find an open in the terminal 2 black ground wire?

hpdude02

Sorry for the delay, I am on travel. I connected the light between the battery hot terminal in the fuse box and the ground terminal 2.

Also discovered that the air conditioner is not working, although the heat does. Not sure if the AC compressor circuit is also not working.

hpdude02

Was finally able to solve this. Before the alternator went, we had a new battery installed. It is possible that part of the wire harness from the fuse box was caught under the battery when installed. I found 3 severed wires, all were small gauge wires, one belonging to the blower motor relay and one belonging to the condenser fan relay. Not sure about the third. Reconnected the wires and everything works.

RonJ@HT, thanks for your help.