Problem with AC/Heater Blower Fan
 

I have a problem with my blower motor that I need help with. My car is a 1993 Honda Civic Si HB with 88,000 miles on the body. The engine, transmission, suspension, brakes, and ECU are from a 1997 Type-R and have 30,000 miles on them. I also have AEM True Power under drive pulleys for the power steering and alternator.

The problem that I am having is that the blower fan on my AC/Heater does not work all the time. When I start the car up it usually doesn't work. If while I am driving I turn the car off and then back on (while I am rolling) sometimes the blower fan will start working. When the blower fan is working it blows cold (if AC is on) or hot (if heater is on) air and works great. When I go to work in the morning the turn off and then back on again trick usually works every time on the first try. Later in the day when it is hotter it usually does not work until several tries. The fan has no other problems. It works at all blowing levels and once it is on it does not ever shut off unless I turn it off.

The only theory I have right now is that the blower fan is operated by some sort of relay switch. When the car is started this relay switch does not get energized because the car has an under drive pulley and does not provide enough power. This theory is a long shot because I do not know how the AC/Heater fan works.

Has anyone else experienced a similar problem? Anyone have any ideas on what the problem may be? Anyway willing to scan or email me the debugging section for the blower fan in a HELMS manual? I have a HELMS manual for the car but I cannot find it.

Thanks in advance to anyone that can help.

- John

You may be partially right with the relay.... it sounds like either the relay is sticking, or you have an intermittant blower motor (the windings may be starting to open) or some bad wiring somewhere. Now, the fan speed switch on the dash.... does this happen in all 4 speeds or just on one or two of them. I do know that the resistor grid on older Honda fan speed controllers tend to go bad. They can either blow a resistor or a contact can become intermittant/corroded (moisture, temp. extremes, etc.) If I were you, I'd buy a Chiltons manual (or similar) and check all the things I mentioned to you about.

It either doesn't work at all for all four speeds or it works for all four speeds. Because of that behavior it makes me pretty sure that it is not the fan speed controller (although I could be wrong).

Here are some tests that I ran. What I did was try turning on the car but not starting the motor and seeing if the blower would work. I then tried it by turning to the On position, testing blower, then turning motor on, then testing blower. Here are the results:

(1) Turn to On - Blower didn't work.
(2) Turn to On - Blower didn't work.
(3) Turn to On - Blower worked.
(4) Turn to On - Blower worked, Turned motor on - Blower didn't work
(5) Turn to On - Blower worked, Turned motor on - Blower didn't work
(6) Turn to On - Blower worked, Turned motor on - Blower worked
(7) Turn to On - Blower worked, Turned motor on - Blower didn't work
(8) Turn to On - Blower worked, Turned motor on - Blower didn't work

I did all of the above tests sitting in my garage. The interesting thing is that the blower didn't work the first two times just turning to the On position in the ignition but the 3rd time did. Also after it started working it worked every time therafter in the ON position but did not always work once the motor was running. Very Odd. I am really stumped on this one now. Anyone have any thoughts or suggestions? Anyone have a HELMS manual that can scan the pages for the blower fan or that can walk me through the debugging via email?

Thanks,
John