jeff spahn

After a run of bad electrical gremlin attack, my a/c condenser now needs to be replaced due to the headlight motor arm slicing through it.
The 928 headlight system has a very complicated relay setup and if you throw DRL's in there, it gets even more so.

What happens is the headlight motor has two electrical contacts that signal to the relay to provide power either forward or reverse to raise or lower the headlights. If this signal gets disturbed in some way, the headlight motor can continue on its merry way and slice through your A/C condenser, like the picture below:



This can be a very expensive proposition if you can't find a used condenser. At the time of this writing, the new condensers, of the same design, were going for $895.00. There have been users who have successfully adapted newer design condensers to our cars for $200 but that is beyond the scope of this discussion.

What is needed is a shield, made of metal that can be attached via screws to the floor of the car, zip tie to the condenser itself or some other manner to merely stop the headlight motor arm from continuing on through the tubes of the condenser.

Once an offending situation happens, it is merely a matter of shutting the lights off, unplugging the motor from the wiring harness and either winding the motor backwards via the manual **** or removing the arm and dislodging the wedged condition. They you can figure out your electrical issue without having to take the whole front of the car apart to get to the condenser and spending $1000 to fix your issue.



What I would propose is a slotted/vented shield made of stainless or powder coated steel that is around 12" high and 3" wide. The vents would be to reduce and negative cooling effects the placement of the shield may cause.

Something along the lines of this:


I am going to have a local sheet metal shop make me a prototype out of stainless and I'll attach it to the condender via those little passthrough radiator things that you attach oil coolers with.

jeff spahn

Here is a shot of the condenser with a tape for scale.




What I am going to do is have a plate made up like I showed an example of. I'll make it 2" x 6" and slot it for airflow
I can attach it to the condenser with these:



Sorry about the stolen picture but it's all I could grab at work.

I'll try to have my friends shop get me a prototype next week and see if I can get a cost worked out for users.

davek9

Good idea on the shield!
Jeff you should note that this would be for S4 ('87) and up as the earlier cars have a fully rotating motor (shorter condenser).

One question, what would the strain of hitting the shield do to the motor and or moving parts, blow fuse?

Thanks,

Dave

jeff spahn

Dave, when mine hit it just stopped and jammed. I don't know the answer to that but I bet Alan does. I ended up unplugging the motor and prying the arm off the splined shaft. It wouldn't move it was in so tight.

Rob Edwards

Nice pedicure, there, Jeff.

jeff spahn

Thanks, my local Chinese girl works hard to keep me looking pretty for my lady.

Alan

The headlight motor is not designed for continuous operation, nor stalled operation. If stuck driving for extended periods it will get very hot.

It might blow a fuse but I think that it's just as likely it may burn out its windings.

So if your motor doesn't appear to be working right - I'd pull the fuse and wind it into place manually until you figure it out.

Alan

jeff spahn

There's your answer and I'll have to put that disclaimer on a sticker or something to CMA so someone who gets their condenser saved by the CondensRsafe doesn't sue me.

Prototype will be done probably by Tuesday. I'll install it on my old condenser and let the arm whack away. Then I'll get pricing done and offer them through Roger most likely as I am not set up to handle a bunch of orders.

martinss

Looks good Jeff. Since you beat me to it I'll wait to buy one of yours after QA testing

jeff spahn

I got the prototype back from the laser cutters today. I have to refine the dimensions so the bars rest over the condenser tubes. Just the OCD in me coming out. No idea of cost. Some thick stainless, 3mm. No way, no how the motor arm is going through this stuff.

GregBBRD

Seems like, no matter which way the motor turns, that mechanism can't hit the condenser, unless the c-clips fall off and the rod swings free.

While the c-clips do fall off, all the time, in the stock application, a tiny dab of epoxy will keep them on....forever.

Seems easier.

Alan

Isn't that rather larger coverage than is needed? seems the target zone is only a few inches in size - I get spreading the load over a larger area - but would't 6" x 4" be about enough?

Will you paint it matt black to blend it in?

Alan

jeff spahn

My motor hit the condenser and sliced through it, not the lever arm that is connected to the headlights but the arm on the headlight motor splined shaft. C clips were firmly attached. Relay failure of the DRL let motor just keep on a going. Had to remove c clips to get the arm off.

I was really hoping for an "attaboy" from Greg for developing this. Oh well

jeff spahn

I am thinking powder coat black or leave stainless to show your are protected.

7" is going to be next size tried. Should be enough (that's what she said!)

GregBBRD

I'm not saying it's not a great idea.....

I'm just trying to envision the failure mode that allows that arm to contact the A/C condenser.

I've replaced more than a couple of these condensers, from the arm coming off once the circlips are gone.....I've seen this failure "punch" that rod through both the condenser and the radiator.....very ugly....very expensive.

I'll have to go look at a vehicle to see how the splined arm can hit the condenser without anything coming loose.

Before I go look....help me get my head "around this"......why wouldn't this happen in "normal" operation and only happen when the motor gets "stuck" and runs continuously?