leolufse

I was pleasantly suprised to find out how little depth the AC controls take up.
I was even more suprised to find out that you can actually take the controls apart. The display portion is only about 1.25" deep. I may not even have to build any type of enclosure for it. I think I can mount it to the ceiling and trim an opening in the headliner to trim it out.

Instead of running the whole assembly up to the ceiling, I'm planning on leaving the "brains" where they plug into the harness behind the ashtray and just extending the wires you see in the second picture. There are only about 8 or 10 of them. Do any of you electronic guys think there might be an issue if I extend these small gauge wires that are only about 4" to about 72". I'm concerned about a resistance problem and possibly shorting out the unit.
:confused:

TheWacoKid

The only way to know is to try it...I don't know what the tolerances of those chips are. I guess it is possible to overload the sending unit...but I really doubt it. If you are worried just use heavier gauge wire. It looks like it uses something like 24 gauge there...just use 16 gauge speaker wire.

EatRice

I am no expert on what you are doing but I do know about problem I have had and have seen when trying to extend a wire harness like that. I would consult an expert first.

rbartick

Resistance is determined by wire size and length. Thicker wire has less resistance. I cannot really think of a reason why your project will not work as long as your splices are solid (soldered) and your extra wire is thick enough to avoid excess resistance. I never tried what you are doing and I did not take a look at the circuit schematic so it is possible that I am wrong.

leolufse

You think like I do :smash:

It seems like the next logical step would be to extend the wires and do a test before I start cutting the headliner. :yesnod:

TheWacoKid

:iagree: Just remember to use larger gauge wire....I would just go buy a spool of 16 gauge speaker wire and use a couple equal length pairs. :smash:

NOT-MEE

Just my 2 cents
I used to design medical electronics and also was a staff Electrial engineer for a cable assembly shop.First i would use good ribbion cable for the extension use good stuff like 3m spectra strip makes a good one also.Use solid not stranded it is a little hard to work with but it will work out best.look at what you have now gauge size step up one size atleast i would go to at least 16ga looks like the wire you have is 20ga sxl.
try to find something with the same electrial properties.I woould get new connectors for the boards as soon as you remove the wires the connectors on board as about shot and they are gauge spacific.Your Connections will be the crutial step.all i can say is try it it should work.

bgood

I have a spare HVAC head unit that I can give you to work with. It was the original one off my 98 that has the dimming display issue. However it will work well for testing the new setup.

I will bring it to the lunch gathering today.

leolufse

:cool:

I have decided to try and use category 5 e connectors. They are the plugs used in hooking up the data cables to the high speed outlets in a modem. There are 8 wires in each plug and they sell pre-made lengths of connector cables. So all I need to use it 2 female connectors (one on each board) and the connector cable to run from the ceiling, down the A pillar, to the "brains" behind the dash. Simple as plug and play :smash:

85 Stalker

Show us how this turns out! :cool:

I've been contemplating switching the slide/**** control unit in my 85 to an electronic pushbotton control. Has anyone ever done this?

NOT-MEE

there is too much loss on a cat5 connector after you figure the cable and connectors on both sides you are going to have quite a bit of signal loss

MEATHOUSE

Honestly i'de bet money that it will work just PERFECTLY! Everyone said that you couldn't extend an IDE ribbon cable more than 3 feet and that even that was pushing it. Well guess what... I have one running as we speak that is 7' long, yes 7 FEET long!!! I built this soldering 5 strands of cat5e twisted pair to the stripped wires from the ribbon. It plays Dvd's with no problem. This is how i am going to dump the brains of my XBOX in my trunk and have the DVD drive up in the glove compartment.

Justin

Go for it, what do yo have to lose??? :flag

leolufse

Do you think the potential signal loss could cause the unit to not work, or be potentially dangerous (start a fire for example).

Here is what I'm doing with the "spare" AC unit I have. There are 11 wires total, so I'm going to do 5 in one connector and 6 in the other. The adapter cables come pre-made in 3', 7', and 15' lengths. I'd like to use the 7', but i'm not sure that will be enough to go from the ceiling, down the A pillar, and back to the center stack.

I'll give it a shot this weekend with the "spare" unit and see what happens.

Here are some pics:

rbartick

I would not bother with those connectors. They will be nothing but a potential source for a problem in an environment that is subject to a lot of vibrations and changes in heat/humidity.

Solder & seal with heat shrink.

leolufse

I wish I was skilled enough to solder those little guys. The wires are so small, I'm afraid the heat could conduct to the board and mess something up. Besides, look that the second pic where the wires are pressed into the connector, same idea as the connector. I suppose I could have just removed the wires from the board connector and replaced with just the 5e cable itself instead. Hmmmm. :confused:

rbartick

If you use a 25 watt iron properly and pre-tin you will not damage anything.


[Modified by rbartick, 5:15 PM 1/23/2004]

Tony @ MPH

Ummm... I'm not sure where you got that info from. On CAT5 10bt and 100bt are good for 100 meters. Unless he's trying to wire his AC controls in his neighbor's car it should be fine. I am not sure how well CAT5 carries voltage but for just plain signaling it will shine like a star.

If CAT5 doesn't work you can always go for CAT5E or (more expensive) CAT6.

Tony @ MPH

Sounds like a splendid idea. Note that if you have trouble with CAT5 or CAT5E you can always go to CAT6.

NOT-MEE

i dont think you are getting my point data and logic more than likly the controls read veriations in power or impedance or a digital data bit stream if you decrese the span between the signals the logic will not work.I dont think you are going to have a problem at all with fire this is low voltage.I just might not work or it will have sluggish results..As to the question about solder insulation on auto wire is now primarily XLPE cross linked polyeheline (sp?) http://www.thomasregister.com/olc/sm...ils&ptno=11320
look at the specs.HERE IS A LINK TO THYE CONNECTOR MANUFATURER http://www.hirose-connectors.com/con...connectors.htm.I thiink it will work but you might need to make some adjustments.Re: connections and wire


[Modified by crash1mac, 8:53 PM 1/23/2004]

NOT-MEE

Ok the difference between cat 5 cat 5e and cat 6 This argument could take days is the number of twists per foot and the way it is placed inside the jacket. Do a search and look for specs.http://www.anixter.com
Control cable is different is has a lower loss and a different ohm rating .As to you question where i got my info? 16yrs of electronic design and imaging experience . And a little piece of paper on my wall.
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