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by John Cirillo (71_Dart)
My 1986 Dodge Aries had been running with just one lamp on the Heat/AC control for a long time. I had looked at it a few times with the instrument panel covers off, but saw no lamps to replace. This puzzled me, but I didn't have time to investigate.
I have the Haynes 30008/723 manuals, the Clymer A293, and the Chrysler 1986 FSM for front wheel drive cars. Each of those manuals shows a couple of different Heat/AC controls, and one or more describe briefly how to change the lamps. But none cover changing the lamps on the above pictured control panel. Having learned how to do it, I can see why. It can't be covered in a few words.
Today I was working on the instrument panel and decided it was time to figure out the mystery before the last lamp went out. If your Aries or Reliant or other K car model has a Heat/AC control panel similar to the one above, this article will show how to replace those lamps. I actually removed the whole control unit to figure this out, but once I did it, I realized this was unnecessary.
To get to the Heat/AC control panel, first the upper and lower instrument panel covers need to be removed.
This is fairly straightforward and is thoroughly covered in any of the above manuals, so I will skip that part.
When you get to the point where the mounting screws for the Heat/AC panel are exposed as seen below, then you are almost there.
Showing the Heat/AC panel after instrument panel covers are removed.
Here I've already removed the two screws and pulled the control out slightly.
You will need to pull off the two slider knobs (one for the fan and one for the temperature).
These knobs pull straight out with some difficulty, so I recommend pulling them
before taking out the two screws.
Then slide the whole panel forward a couple of inches. You do not need to
detach any wires or hoses at the back because you are not going to take it out.
Above, the two latches are circled in white. The procedure is to lightly lift
those latches with a small screwdriver while pulling forward slightly on the top of the panel.
Once the latches are unclipped, the panel will swing out from the top
(as though it was hinged on the bottom), and then can be removed.
My photo was made after I reassembled it, so I have the knobs on but
when you are doing this the knobs should have already been removed.
Now you can see the three tiny Number 74 lamps. They are similar to the familiar 168/194 wedge lamps, only smaller.
Before you get tempted to yank them out with pliers, don't! You will crush them and then possibly never get them out.
Read on for the safe way to remove them. (Ignore the pencil for now. It comes later.)
We're going to make a little grabber tool with ordinary tweezers and double-sided foam tape. Cut two strips of the tape and attach them to the tweezers as shown. Remove the backing from the exposed part when you are ready to extract the lamps. Then look at the next photos to see how I did it.
Here are the tweezers hanging by themselves on the middle lamp. The tape is quite sticky at first.
As you go along, if the tape becomes dirty it will lose its grip in a hurry. Just make some more strips and reload the tweezers.
Here I am pulling out the middle lamp with the tweezers. The lamps are stubborn and possibly corroded so it may take several pulls. Just keep at it. Change the tape if it loses its grip.
At last! Here's that lamp. I have already removed the other two. By the way, change all of the lamps!
Even if one or more are still working, it's pointless not to change them all now.
This is what to get. Too bad they come two to a card and you only need three! I got these at Pep Boys. Neither of the Auto Zones in town had these in stock, though they had a peg for them. These lamps are ridiculously overpriced compared to other lamps, with no apparent reason. Supply and demand, I guess. You could order them from Mouser Electronics for about 60 cents each but they have a $20 minimum order.
This is an old lamp, but this is how to load a lamp onto the tweezers for installation.
Note that the wedge base must be vertical like this when you plug it in.
Getting ready to plug in the lamp. Same posture as taking it out.
Guiding the new lamp into position. They are reluctant to go in. Having new tape helps a lot here. You'd think plugging it in would be easier than pulling it out, but that wasn't the case for me.
At least if you can get it started, go to the next photo to finish the job.
Once the lamp is started in the socket, it can be pushed home with a pencil eraser.
After you have all the lamps in place, it would be a good idea to turn on the lights and make sure they work.
I didn't need to do any cleaning on the sockets, not sure how I would have done that.
After confirming all is well, reinstall the Heat/AC panel cover by hooking the bottom latches onto the bottom of the control, and then swinging the top of the cover into position so that the latches click in place. Slide the control back into position and reinstall the two screws and two slider knobs. Reinstall the instrument panel covers.
Here's a sight I hadn't seen in a long time.
This is my actual Heat/AC panel with the new lamps installed. These lamps should last for several years.
I hope I didn't leave out any important steps. Let me know if I did. The main difficulty was getting the lamps to come out and go back in. Tweezers and tape might not be the best solution, but there is no way to grip those small lamps with bare pliers without crushing them. I know this from experience.)
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