Fresh Air Blower, It worked on the bench Options

[DennisV]

The fresh air blower on our 1970 914-6 does not work. No air. No sound. No light.

Is operation of the fresh air blower dependent on anything other than:
1. battery
2. #8 fuse (15 amp windshield wipers, ventilator, horn, cigarette lighter)
3. sliding the lever on the dash

I am not seeing a relay listed on my wiring diagram or in the Workshop manual diagram of the engine bay relay board. There is no relay?

There is no associated switch? Just the slider?

My blower did not work. I pulled it and refurbed it. Bench tested working. Also cleaned the contact traces on the board with the sliders in the dash. Back in the car (after lots of cursing). Doesn’t work in the car (more cursing). (IMG:style_emoticons/default/mad.gif)

The horn works, so I know it's not the fuse. I unplugged and reseated the plug on the back of the blower.

I see a brown wire coming from the slider board. My diagram just says From: Male, To: ground instrument panel. So I'm not sure where it terminates.

Thank you.

[DennisV]

I have subsequently tried a few things. Still no joy.

I can detect 12v to both the bulb socket on the slider controls and one socket on the plug that attaches to the blower.

I tried a jumper wire between one of the speed wires and a ground lug. No affect.

[tygaboy]

I've been playing with the blower fan wiring on the Ferrari build and found that unless you are absolutely sure that the fan speed contacts REALLY are consistently in contact as they should be, the connection isn't reliable. In the case of the one I'm working with, it wasn't just cleaning things. The moving contact "arm" needed to be bent so it put more force downward as it moved through it's range and solidly touched the other contacts. I also added a bit of dielectric grease to all the contacts. That seems to have solved it for me.