1990 climate control

[Larryejoh]

I am trying to get my a/c working on a recently aquired 90 Reatta. The climate control temperature will only go up and not down. I pulled the battery cable and it started at 78 degrees but will only toggle up from there. I guess the climate control is bad and cannot be fixed?

[ChrisWhewell]

Mine had the same problem. The contacts on the buttons are oxidized. The fix has been put up on these boards by Barney Eaton, and involves removing the unit. Then, cut strips of paper 1 cm wide and 5 cm long and soak them in a volatile solvent, such as a naphtha (Ronson lighter fluid) or mass airflow sensor cleaner, and insert the wet strip between the contacts, apply slight pressure to the switch as you pull the solvent-soaked paper back out. Repeat for each button switch. The paper I used was Post-It notes, it worked great

Edited August 14, 2017 by ChrisWhewell (see edit history)

[Larryejoh]

Thanks. I don't have a manual. What is involved in getting the  dash surround off around the climate control display?

[jonlabree]

Couple of screws in each air vent and then it snaps off carefully.

[Barney Eaton]

Attached is a photo of the control unit opened.

 

To get to the dash components,  there is a screw in each end air vent......the 1990 also has 2 screws in the overhang above the instrument cluster....'91 does not have those screws.

using some sort of tool with a 90 degree bend...slip it behind the bezel and pull out.  I slide the tool along the crack until I hit one of the spring clips then pull.  Once you get the bezel off, you will see the screws that

hold the radio and a/c controller in place, you will need to pull both the radio and a/c controller out until you can get to the screws that hold them together.

I am also attaching a picture that shows the connector and a screwdriver in the crack separates the connector.

Note the black plastic strip with the grey buttons...you must get the cleaning paper under the grey buttons.

[Larryejoh]

Thanks for all the help.

 

Larry

[Barney Eaton]

Here is an additional picture, closer view showing the strip of paper installed under the grey button

[89RedDarkGrey]

Why not simply separate the boards to clean? They appear to be the same as most IR remote controllers- carbon impregnated tip silicone buttons. I guess this method is physically easier, as long as the proper cleaner is used, such as THIS. Isopropyl alcohol contains water, and could leave residue. 

 

HOW THEY'RE MADE

Edited August 30, 2017 by 89RedDarkGrey (see edit history)

[Barney Eaton]

The reason I do not separate them is that black plastic backing is heat staked on the other side of the PC board.

If you cut the heat stakes then you need some method of reattaching the black part to the assembly.

Small screws might work but some of the staked pins are on the very edge of the black plastic, reducing the area you would need for screws.

[Larryejoh]

I cleaned mine with paper and Radio Shack contact and control cleaner. So far it works great.

[89RedDarkGrey]

On ‎8‎/‎30‎/‎2017 at 9:09 PM, Barney Eaton said:

The reason I do not separate them is that black plastic backing is heat staked on the other side of the PC board.

If you cut the heat stakes then you need some method of reattaching the black part to the assembly.

Small screws might work but some of the staked pins are on the very edge of the black plastic, reducing the area you would need for screws

 

If one absolutely had to separate the pieces- you could easily use a "low temp" hot glue. Most electronics now days use it to pot stuff in place; it's referred to as "Hot Snot". I also suggest to never use an abrasive of any kind to clean the pads- even 3k w/d sandpaper would do damage.

 

3 hours ago, Larryejoh said:

Radio Shack contact and control cleaner

 

Since they are out of business- you can still use the equivalent-  

[89RedDarkGrey]

I wonder what modern LED would look like in place of those incandescent bulbs, and you could even change the color of the amber ones, too if you wanted.  I can imagine- their lifespan is nearing thousands of hours by now. Are they just pushed in- socketed, or soldered?

[Barney Eaton]

I suggest you take one apart, do your thing and report back.

[ChrisWhewell]

On Wednesday, August 30, 2017 at 6:00 PM, 89RedDarkGrey said:

Why not simply separate the boards to clean? They appear to be the same as most IR remote controllers- carbon impregnated tip silicone buttons. I guess this method is physically easier, as long as the proper cleaner is used, such as THIS. Isopropyl alcohol contains water, and could leave residue.

 

HOW THEY'RE MADE

If interested, you can obtain 99.9% isopropanol from electronics supply stores, such as Fry's electronics, its $8 for a quart.  

[Alchemist]

Hear, hear!  Cleaned my contacts this morning using strips of a 3x5 index card and contact cleaner.  Works perfectly now and took about 30 minutes complete.  The only scary part of the process was removing the bezel around the instrument cluster.  31 year old plastic can be amazingly brittle.

[steven 123]

thanks for the tip guys i just removed mine and sprayed contact cleaner and paper as you suggested....works like new....thanks again