I thought I would post this thread in case others are looking at how to replace their 2-speed heater fan switch on a non-AC car. This switch came out of a 1974 Duster, but I suspect is has a fairly large application.
While my brother was in town helping me with the Duster, we needed to disconnect the fan switch. While trying to be very carefully loosening the plug-in, the small board on the back of the switch disintegrated. I knew from a previous search that my specific switch was not being remanufactured and switches on eBay were rare and pricey. Fortunately, my brother has 20+ years in avionics for the Navy and Air Force, so he was determined to rebuild the switch.
A little research showed the crumbled board (Pics 1&2) was PN 3489677, which was also used on 1972-81 D100's. He found a board pretty easily on eBay (Pic 3). The switch housing was different, but the board is the same. You just need a few tools (Pic 4). When you pull your old switch, you need to bend up the 3 tabs on the back of the switch (Pic 5 - he recommends using a small pair of dikes to carefully turn the tabs up), being careful not to damage the old board as you twist the tabs (Pic 6). With the tabs bent up the terminal board should come out and you will see the sliding contact (Pic 7). There is no up or down orientation on the sliding contact piece.
Use alcohol to clean the switch housing (Pic 8), sliding contact and inside and outside of the terminal connectors. Put a light film of dielectric grease on the sliding contact (Pic 9) and get the sides where the spring keeps pressure on the plate. Treat the inside terminal board contacts and the three outside connectors with dielectric grease (light coat) as well. Put some white lithium grease on the fan switch lever where it pivots.
Put the sliding contact back in (Pic 10) and align the terminal board up with the tabs. Using small channel locks, carefully pinch the tabs back down to secure the board. Go easy and DON'T TOUCH THE BOARD (my brother's emphasis). The rebuild is complete and you can do a quick test with your meter (Pic 11). I can tell you my fan switch works like a new one now' thanks to my big brother!
The photos mentioned above will be posted in a few minutes.
While my brother was in town helping me with the Duster, we needed to disconnect the fan switch. While trying to be very carefully loosening the plug-in, the small board on the back of the switch disintegrated. I knew from a previous search that my specific switch was not being remanufactured and switches on eBay were rare and pricey. Fortunately, my brother has 20+ years in avionics for the Navy and Air Force, so he was determined to rebuild the switch.
A little research showed the crumbled board (Pics 1&2) was PN 3489677, which was also used on 1972-81 D100's. He found a board pretty easily on eBay (Pic 3). The switch housing was different, but the board is the same. You just need a few tools (Pic 4). When you pull your old switch, you need to bend up the 3 tabs on the back of the switch (Pic 5 - he recommends using a small pair of dikes to carefully turn the tabs up), being careful not to damage the old board as you twist the tabs (Pic 6). With the tabs bent up the terminal board should come out and you will see the sliding contact (Pic 7). There is no up or down orientation on the sliding contact piece.
Use alcohol to clean the switch housing (Pic 8), sliding contact and inside and outside of the terminal connectors. Put a light film of dielectric grease on the sliding contact (Pic 9) and get the sides where the spring keeps pressure on the plate. Treat the inside terminal board contacts and the three outside connectors with dielectric grease (light coat) as well. Put some white lithium grease on the fan switch lever where it pivots.
Put the sliding contact back in (Pic 10) and align the terminal board up with the tabs. Using small channel locks, carefully pinch the tabs back down to secure the board. Go easy and DON'T TOUCH THE BOARD (my brother's emphasis). The rebuild is complete and you can do a quick test with your meter (Pic 11). I can tell you my fan switch works like a new one now' thanks to my big brother!
The photos mentioned above will be posted in a few minutes.
