'90 integra heater fan switch

[dlb]

i'm working on a 1990 acura integra that my friend just bought. the heater fan does not work on any speeds, nor does anything happen at all when the switch is turned on to any of the settings. the previous owner thought it needed a blower motor so i unplugged the plug from the resistor pack and checked for power but nothing there.

i checked the fuse with a volt meter and it's good, 12 v on both sides of it.

i checked the fan switch plug, which has 1 fat wire and 5 skinny ones. two of them have 12 volts, one is a ground, not sure what the other three do. but i am guessing all seems fine there too.

so i disassembled the switch and it's really simple. it's a knob that rotates so that 3 contacts are made in each position (similar to the dome light switch in tercels), and nothing appears wrong with it. all the contacts are clean, making good contact with each other, no corrosion, etc. but as a super hokey test to see if the switch is at fault, i twisted a few wires together so they had 3 ends and plugged them in various orders to the fan switch plug. nothing happened at all. i then connected the volt meter to the resistor pack plug to see if maybe both the blower motor AND the switch were bad, but even with my hokey wire test i got no current at the blower motor end.

so i'm at a bit of a loss. if i had a spare integra fan switch kicking around i would simply throw that in to test it, but i don't and don't want to buy one and find i still have the same problem. does anyone have any suggestions on further testing i could do to confirm where the fault lies? i can take some pics if that would help anyone to help me.

[irowiki]

So can you manually apply power to the motor to get it to run?

[dlb]

So can you manually apply power to the motor to get it to run?

do you mean wire a battery directly to the motor? i have not done that but could, to confirm the motor works. i'm more focused on getting power to the motor via the switch though.

[irowiki]

Well it could be some complex wiring thing so was just thinking to eliminate the easy stuff first

[dlb]

it doesn't look like anyone has messed around in there, and no signs of mice or anything that could have messed with the wires. but yeah, i think worst case scenario will be there is a wiring issue and i'll need to make jerry rig something. i might just bite the bullet and find another switch from somewhere.

[irowiki]

I mean you said the motor itself has five wires going into it, which leads me to believe there are some interesting signaling things going on.

[Petros]

I once had a dome light that would not come on, I changed the bulb but it still did not work (the filament in the old bulb looked good). put a volt meter to the connector and I had 12v at the plug, but none at the bulb. I took the dome light assembly out and inspected it very carefully and saw nothing wrong, so I did some resistance tests across the various positions. Turns out one of one rivet, even though tight, was not allowing current. I tapped it with a hammer and pointed chisel in my vise, and got it to work again. The point is that I could find nothing wrong with it, but it had a bad internal contact. I had the same thing once with a simple house light fixture, everything looked okay, but one of the internal contacts had corrosion or something preventing continuity.

You may have the same thing, I would take live wires from the fan and work backwards, verifying the fan works first, and that power flows through each of the connectors, contacts and switches as I work my way back.

[dlb]

i found the same thing on a tercel dome light once, peter, so i hoped for the same thing here. no dice though, the contacts are all solid with no rivets.

but i solved the problem anyway. i was being an idiot, and learned something. i was checking for voltage at the plug for the resistors while the switch was on the 4th (highest) setting. i learned that on the highest setting, power does not go to the resistors. it goes straight to the fan motor then. so i found the plug for that and checked it, 12V on the 4th setting. so the switch was working, i was just looking for voltage in the wrong spot.

turned out it was the blower motor. the fresh air intake seal at the top was dust and it had leaked lots, killing the motor. got a complete motor assembly from the wrecker for $60, installed a new seal on it, and now it works like a charm. on to the other stuff now.