Intermittent blower works when I tap it

[strunch]

I replaced the blower and blower resister on my 99 astro van last year and it has worked fine. However recently the blower quit and then turned on by itself after I restarted. It worked fine for a week and then went off again. I popped the hood and tapped it with a hammer and it kicked in. I understand blowers wear out but I replaced it only last year. The van was sitting for six months unused. Is this normal? Did I just get a bad blower?

[CD Smalley]

Time for another new one in my opinion. They should last longer than that. But it depends on the manufacturer.

[strunch]

Originally Posted by CD Smalley

Time for another new one in my opinion. They should last longer than that. But it depends on the manufacturer.

It stopped working again today and tapping it didn't help. When I got home I checked the voltage between the black and red wire coming from the blower resistor. It only read .2 volts. So I plugged it back into the fan and spliced into the ground wire coming out of the blower and routed to the chassis. This resulted in the blower working on all speeds except high. This leads me to think I have a grounding problem somewhere....or a problem with the blower resistor itself. Any clues where to look next? I'm still working on pulling the plastic reservoir out so I can get a better look.

[strunch]

I found the problem here. I filed off the carbon and everything works now. I wonder what caused this short?

[brcidd]

That is NOT a short- it is arcing from a bad connection- when two connectors are together, they must touch cleanly, without corrosion, if there is limited connection, then heat and arcing is generated-- ever touch a blower hot lead to a battery- you see flashes, or arcs-- this is the same thing- except it is continuous- then it melts the plastic around it...

[strunch]

Originally Posted by brcidd

That is NOT a short- it is arcing from a bad connection- when two connectors are together, they must touch cleanly, without corrosion, if there is limited connection, then heat and arcing is generated-- ever touch a blower hot lead to a battery- you see flashes, or arcs-- this is the same thing- except it is continuous- then it melts the plastic around it...

ahh i see. It's amazing the chaos a bad connection can create. I'm just happy it was a cheap fix.

[CD Smalley]

There is a gel you can get to put into those connectors to keep the corrosion from happening. Looks like you could use some.

[brcidd]

Yeah- the gel I use is Dialectric grease- sold at parts stores everywhere...

[CD Smalley]

That's it! Couldn't think of its name at 5:45AM.