1995 240SX strange clicking in dash

[unichi]

When the car is up to heat, I hear a strange click coming from somewhere in the dash and right after that happens the heater fan either speeds up or slows down. As I drive this happens about every 5-10 seconds with the heater fan speeding up and slowing down. Seems to me like a relay is being triggered which is causing a current drain to the heater fan, but I have absolutely no idea what might be causing this. Should I be worried at all? Could this relate to an overheating problem I have? Thanks.

[vancouverbc]

I think the heater fan is just an electric motor with fan blade. I cant remember how the speed of the electric motor changes. I think this fanwould be independent of your heating problem. It is just a fan and is controlled manually. The electric motors do wear out.

[wrenched_1]

the same thing happens to me in my altima, but only when i have my temp set all the way to the cold setting. i think my problem is just a blend door not knowing when to stop trying to open, so the motor keeps turning and thus making the noise i am hearing. the only way to fix it is to tear the dash apart. so i just dont push my switch all the way over.

not sure if this is similar to your problem but hopefully it helps.

-DAN

[unichi]

Huh, this was happening when mine was all the way hot. Maybe it's an all or nothing kind of thing. I'll have to test that next. I'm also trying to find the wiring diagrams. Anyone know what section they're in, in the Shop manual?

[vancouverbc]

this is for 1991-1994 Diagram blower fan

click on picture to enlarge and then click again for larger view



my first guess would be the switch contacts that change the speed of blower fan in the switch.

[unichi]

SWEET! Thanks for that diagram, that will help immensely.