Blazer heater fan module

:banghead: 2000 S-10 Blazer - My heater fan dosen't allways come on.I replaced the relay'that wasn't it then found out tapping the module,that is on the back of the fan/blower under the hood makes it go on.Replaced it at a cost of $200 and still have to tap it like a bad stater to make it go on.If tapping the module makes the fan go on what happens when I tap it that would do that.Why wouldn't the new module just make it work?

What "module" are you tapping on? There are three components under the hood that involve the blower: The blower motor, the high blower relay, and the blower resistor.

Its the one on the back of the fan.It may be the Heater Control module.It has a bunch of protruding tabs on the back of it that sit INSIDE the fan housing.I think they may be temperature sensors.It plugs into the fan and the wire harness plugs into it.

That is the blower motor resistor pack. On the back side are resistor coils, (look like springs). The more coils the current travels through on it's way to the blower, the slower the fan runs. You might have a poor connection or a blower motor on the way out.

It was a blower motor on the way out.What a pain to put it in,probably would have been easyer if I took the fender off first.With some prying and proding I got it in though,outside during a snow storm.Thanks

Glad you got her figured out, good job! Thanks for posting back.