Jerry,

You bring up good points. I may have to rethink how I accomplish my center console goal, and may have the local fiberglass shop put something together, and perhaps hydrographic dipping might be an option.

Cheers!
Carl

 

I opened up one of my spare HVAC Control panels last evening to see where I might connect to the wires that lead to the five male pins on the outside so I could make a different kind of connection somewhat remote from the outer body of the control. What I found was the the five pins are part of a control box inside the unit just behind the **** and are not exposed to any access. I think that means that I, or you, are back to the idea of connecting onto the five pins from the outside.

I am reluctant to try to solder to the pins on the outside for fear of melting their plastic housing, so I am still looking for female bullet connectors in the 90 degree or right angle configuration and that are not too tall. The size of the male bullet is .157 inch diameter. I have some that are straight, but I think it will be difficult to bend them into the right angle shape, but I may have to try.

When it warms up a bit I'll be making the trial fit of the modified center console in the silver 928. I see some warm weather on the west coast may be on the way here, so soon I hope.

 

Jerry - thats just the switch portion - seperate. I should have one somewhere, I'll see if I can find it and take a look at it re: this pigtail idea

Alan

 

Thanks, Alan. I appreciate you input, as always. Those five pins are the ones that I am troubled with. The other connector to all the contacts on the edge of the circuit board I don't think are an issue.

 

OK Jerry - found it:

I took it out and it is completly separate - remove the friction fit drive cog at the front and you have a single nut securing the whole module.

The bad news - the terminals are an integral part of the switch and can't be removed without compromising the switch function. I chopped off the connector housing and power filed it flat* - then hacksaw cut and power filed the terminals down to create sufficient clearance. I think you can easily solder to these, cover with jb weld for mechanical & electrical protection and also secure the pigtails to the main case after reassembly. This is the only way I see it working out... Since the pictures I've cleaned up the posts more, cut some keyways into the remaining posts for more surface area for mating the wires when soldering, I think it will work very well.

You are welcome to have this modified switch unit if you'd like it (keep yours pristine and try this out...?) - let me know.

*BTW you should at least get yourself a power file for the kind of work you do it would have a real payoff (and maybe a dremmel would too). The power file is one of my favorite tools (after a drill and screwdriver - I use it more than anything else - I would never have imagined this - but its been true for the last 10 years).

Alan

 

Thanks, Alan, for digging into the AC control so thoroughly. I think something like what you suggest is where we will end up. From your pictures I am wondering if it might be as good or better to drill each of the ground-off pins and tap for a small, maybe 4-40 screw and attach the pigtail to them that way rather than trying to solder the wires onto them. I am still afraid of what the heat will do to the poastic that the pins appear to be bedded in. Then, I wonder how deeply the pins can be drilled.

Thanks for the offer of the switch unit. I have no problem with modifying one or all of mine that will be used in this conversion.

 

Jerry - I further modified this last night - I think the slots allow good wire location - side exit (I might do 45 diagonal if I did it again) and more solder contact area - including a neat cap over the top. I also lowered the profile more. The plastic will be fine if you can solder quickly enough - its tough stuff.

Pre-tin the terminal, pre-tin the wire and quickly assemble, add a neat solder cap - done! I think I will add a pigtail to mine today...

Jerry -


Mine is much older model - bought it in the UK - loads of choice of 240v euro models on ebay.uk.com but very little usage in the USA - no idea why. Until now any 110V models usually were very expensive - this is only ~$50.

I think you would find it very useful indeed (you'd probably end up with even more dust on the floor though...). I look at stuff and say to myself "should I cut that bit out? - nahh I'll just file it away"

Alan

 

Alan, there is room enough under the edge of the upper insert for the entire pin plus about an eighth inch or slightly more for a right angle slip bullet female connector, so I don't think there is a need to grind actually any of the pins off. Too, If I follow your lead on these pins I might just drill a hole sideways through them and solder the pigtail wires in the holes. Then I think I will still try to make a male connector that will allow a user to plug and play into the original female connector in the car so that will not have to be changed. I think I can do that pretty simply with some pieces of ABS and some glue together with the bullet male connectors, of course.

 

Alan and Jerry,

Following this, although it doesn't apply to me (with the only '94 in the US with rootwood option original, I'm not going to change that!).

But, it's always seemed to me that I'd PREFER to have a rheostat for fan speed rather than the 4 options provided by Porsche. Since you are doing a lot of work to modify the HVAC controller, do you suppose that would be an option as well?

Gary

 

Gary I agree - but that is more of a user option for install than a part of Jerry's plan (I think...). Its important to be able to retrofit the stock AC Head but any modification beyond that you'd be on your own.

While due to the independance of the blower control it would be possible to swap this for a potentiometer (its on the same panel as HVAC temp/flaps - but quite separate) - you'd need a separate controller to make that work (located somewhere it can get hot - similar to the blower resistors - maybe the same place). You can't use a power rheostat in the head unit due to power dissipation - for the power levels required it would need to be truly massive anyway and wouldn't fit.

So you need an electronic variable speed control - I have one for test purposes and it works OK - a PWM (FET) controller. However you have to rewire the blower motor since the FET switching really always needs to be on the ground side for best (& cheapest) results and the stock setup is on the +supply side. Very doable but real work.

However I'd not ONLY change the blower - we need other revamping in the head unit - for both looks and function - so I think a whole new HVAC head is in order - But thats a whole new project - goes with this for sure - but an independant modular idea of its own.

BTW I hacked up the blower switch because:

1) Its a spare old one I have - and they really are very reliable
2) Eventually I won't even need the primary one let alone a spare...
3) I always wondered about the switch internals

...and I like to help out Jerry with ideas so he can get on with making cool stuff

Alan

 

Ahh so now I can find this thread again (something funky happened there for a while on the IB side...)

Jerry, here are some photos of the pigtails - hopefully you can tell if they will fit OK. I think you have to run them external - but looming them and attaching with a couple of cable clamps to the case should work fine.

The soldering is not as neat as I'd like on the 'caps' - but its a compromise between neatness and overheating the terminals - a bigger soldering iron would have been good - the terminals have a lot more thermal mass than I thought. Still it works pretty well. I used 12AWG on all the terminals, could have used 14AWG on two of them. I had to trim the case a little (powerfile!) where the wires exit. I'd still use the WeatherPak type connector I showed. If you have to specially fabricate a mating half connector - its easier to just chop the old one off and make a fresh connection. Nobody who is doing this is looking to keep a 100% stock car...

Again, Jerry you are very welcome to the already modified switch if you'd like it.

Alan

 

That looks great, Alan. I think they might be better going off in the opposite direction since they are on the left side of the switch body and they connect toward the front of the car, but there is plenty of room to make the turn under the console. Actually the only two that have a clearance issue were the two closest to the front of the unit. the rest of them are not up inside the upper insert, so they are not an issue, except for the need to use only 3/5 of the female connector, but too, the original connector may not reach the new location. Nice job.

I'll probably be doing something much like this with one of my units, but I appreciate your generous offer. Thanks.

Let me know, Alan, and I'll put a kit together for your project.

 

The White & White/Green wires (terminals 1 & 2 - closest to the front panel could be 14 AWG if it would help you).

Alan

 

Jerry - I will take a kit (I have all the other big stuff you have made so far..!) - but I'm just too busy to jump on it now so I'll let others go first here, maybe in a month or two I'll be ready.

Alan

 

Jerry its certainly already headed towards the front end of the car already... just under the HVAC head unit rather than over - is that what you meant? can easily be done either way... you do need to remove a little part of the case for clearance on whichever side you choose - but this has the switch body right under it anyway.

Alan