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| Heater Controls |
Last November I took the Mitsubishi to the mechanic to get the heater fixed. The first problem was the controller so I bought a couple of used control panels off of E-Bay. Took them into the shop and find they are the wrong parts. What it needs is new actuators that CONTROL the flapper valves in the heater box. So I order a couple of actuators and find they don't fit. The old, defunct actuator has a seven pin electrical connector and one of the new ones has five pins and the other has three pins. Wonderful. Search the internet and find nothing. Find a list of junk yards and start calling. I called a dozen and found nothing. I even posted a note on the national junk yard board but got no reply.
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| Actuator Internals All the lines on the gear wheel are wear marks, there are actually only three wide lines of conductive paint. |
Okay, let's take a look at this actuator and see what's going on. Open it up and I find a small electric motor turning a gear train. That part looks simple enough, but why do we have seven pins? Take out the big gear and I find some some brass brushes that contact the underside of the big gear. There is a spiral of something on the gear. It looks kind of erratic and my immediate impression is that it is some kind of pattern that encodes the position of the wheel.
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| Circuit Scribe Conductive Ink Pen |
I take it to lunch and confer with my cronies and Jack suggests that it is resistive paint. The erratic pattern is simply where the paint has worn off. So I order a conduction paint pen and fill in the worn spots and put it back together. Put it back in the car and it seems to be working okay.
Electrical Testing
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| Test Leads Kit |
Before I got to the paint, I thought I would see if one of the other actuators could be made to work. They all used the same case and the same drive shaft, just the electrical connectors were different. Though mine has seven pins it only uses five. Looking inside the 5-pin actuator, it seems to be very similar, so I thought to hook it up to a meter and see how it behaved. I have a collection of test leads, but none that were small enough to connect to these pins, so I bought a kit. Still had to drill holes in the shell surrounding the connector on the actuator, but I got them all connected. Hooked them up to the meter and a battery from a drill, and ran the actuator through it's whole range of motion. The resistance on the original actuator ran from zero up to 8K ohms, on the new actuator it varied from 0 to 6K ohms. Six is almost the same as 8, right? Or so I reasoned. I tried it but it would not go through it's full range of motion, so we're back to the original.
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| Lever Wire Nuts |
Mounting Screws
The two screws that were holding the actuator in place had gone missing, so I looked through my collection of screws and found a couple that seemed to be just right, except they were just a fraction of an inch two long. I used a couple of nuts as spacers and they worked fine.
The screws are like sheet metal screws, so anything that was approximately the same size would of worked, except one of the screws was buried way back in the dash so getting any kind of driver in there was difficult. So I wanted a screw that was as near to correct as I could find.
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| Right side underdash panel |
The actuator wasn't hard to get to in spite of being buried in the dashboard. Just pull out the glove box which is held in place with four screws that are easy to get to. I ran into a little problem when I was putting in the screws holding the actuator. I was using a little screwdriver bit about two inches long to get one of the screws started and I dropped it and it disappears. Bah. There is a panel on the underside of the dash that is held in place with another four screws. Take those out, the panel comes out and there's my screwdriver bit. Get the actuator installed and now we have to put that underdash panel back in. This is a real struggle. With the panel in place you can't see where the screws go, and I can't get my head in the footwell far enough to see anything. I probably spent an hour getting those four screws into their holes.
Expenses:
I could have returned some of those parts, but I fumbled around and now it's probably too late.
Notes:
- I started this post on March 15, 2024. Then I got distracted, but now I've finished it.
- I've tried several different ways of including a table in a blog post but none of them worked very well. Today I thought I would just try copying the data from the spreadsheet and pasting them here and it worked very well. Just highlight the rectangular area you want and press Control-C to copy it, move over to the blog and press Control-V. Worked very well.
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