EATC acting up...

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brokencase
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EATC acting up...

Post by brokencase » Tue Aug 14, 2018 7:27 pm

Another minor interruption of Scorpio bliss... This started up about a week and a half ago...

Every once in a while the EATC will shutdown. By shutting down I mean that the display goes totally blank, no LEDS.
You can't even turn it back on. But I find that if I go to work and it shuts down....when I leave at the end of the day it is
back up and running. I have also seen it shut down and magically turn back on on the course of a longer trip.

It does not seem to happen if I am running with A/C on. At least I have not yet seen it happen in that case.

I have seen it happen with the unit turned off or if I have it set to economy mode (a/c off) 72F fan low.

Seems like a loose connection. I checked and cleaned the associated fuses/contacts. Thought that might have been it
because it did not happen for a while after that - until today.

Looks like next step is to pull the unit and clean the connector on the back.

Just wondering if there are any known loose/cold solder joint issues EATC previously discovered by other members.
Checked the archives and nothing to that effect.

Outside of this my EATC is working fine. I am getting no EATC error codes.

I am actually pretty impressed how well the A/C has been working this summer.
So long as I keep her parked in the shade and put the front window sunscreen up.

brokencase
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Re: EATC acting up...

Post by brokencase » Tue Aug 14, 2018 11:20 pm

Here we go...Found this on the forum search....

Dried out electrolytics...Probably will be the number one failure mode of Scorpio electrics as we move into the 4th decade...:)

http://forum.merkurclub.com/forum/viewt ... TC#p240760

Quoted
" Well, I fixed the EATC issue.
The blinking and clicking has stopped and normal service is resumed.

The rapid blinking of the lights with the on / off temperature display, coupled with the clicking from the side of the blower motor housing (which was the de-icing switch) and the unstable running of the blower motor suggested either a control circuit issue or a power supply problem. Some of the sensors may be defective but they usually fail open or closed circuit when they fail, they don't vary their output, so it is unlikely they were the cause of the problem.

I dismantled the EATC and inspected the PCB for dry joints. I found one and re soldered it (though I doubt this was a contributor to the problem). I then checked the power supply rails and voltage regulators. Although everything looked good I decided to remove the electrolytic capacitors in these circuits to test them. The one 220uf was OK, one of the 100uf was OK but the other 100uF and the four 47uf capacitors were all defective. These do degrade over time, especially if subjected to excessive heat, so I was not surprised to find these were no longer in spec.

Good practice is to replace all these capacitors, not only the clearly defective ones, so that's what I did. I reassembled the EATC, reconnected it and it worked. No blinking or clicking and the blower motor runs smoothly and consistently.

I'll find out if the control circuitry and all the sensors work when I get the refrigerant checked and the compressor hooked up. I'm hoping someone removed the compressor belt because of the inconsistency of the EATC, it certainly would have made the compressor turn on and off repeatedly which would have been annoying, let alone a challenge for the engine.

On to my next issue. As and when I get stuck I'll be back again for help.
Thanks to everyone who took the time to read about my problem (thanks Darren for your feedback)."
Last edited by brokencase on Wed Aug 15, 2018 9:07 pm, edited 1 time in total.

Ed Lijewski
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Re: EATC acting up...

Post by Ed Lijewski » Wed Aug 15, 2018 11:18 am

So...keeping the car out of sharp sunlight as much as possible when not in use, using a windshield sun deflector when you can't, might prevent or at least delay this issue. Seems reasonable as a preservation tactic given the conductive heat load on the dash for half or more of the year.

YMMV.
Descartes: "Cogito Ergo Sum"
Lijewski: "Sum Ergo Drive-O. Mucho!

brokencase
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Re: EATC acting up...

Post by brokencase » Wed Aug 15, 2018 9:06 pm

It's that dang hot black leather Ed...

Anyhow. I just finished the R&R , dismantling, and replacing all of the electrolytics capacitors in my EATC.
Took about 2 hours.

This is not a job for the feint hearted. I'd say it is up there with changing the odometer gear in the speedo (if you've had that pleasure)

Just got it back in and it still powers up (which means I didn't break anything - woohoo).

The only problem is it came up in Celsius and I seem to recall there is a secret switch to change that.

Here is the interesting part...
I have a tester and I measured the capacitors I pulled...not all were serious failures, but some were really bad...

All caps have a 25V rating...

100uf - now reads 90.0uf vloss 2.0% ESR 0.85
100uf - now reads 59.9uf vloss 1.6% ESR 1.5 <---bad
47uf - now reads 39.3uf vloss 6.7% ESR 3.0
220uf - now reads 81.0uf vloss 4.6% ESR 6.0 <---very bad
47uf - now reads 41.5uf vloss 9.8% ESR 8.4
47uf - now reads 43.2uf vloss 7.2% ESR 7.0
47uf - now reads 31.35uf vloss 10% ESR 6.8 <--- bad

New devices typically have a value within 5% of rated, a vloss <1% and an ESR of less than 2.0 ohms
So all of the above are starting to show the signs of age.

We will have to see if the issue goes away over the next few weeks. But looking at the above data the fix looks promising.

What is the takeaway on all this? Most electrical components are pretty robust over time. Except electrolytic capacitors.
They dry out over time. The 120F temperatures of a parked Scorpio in the sun only helps to cook them off quicker.
There are a lot of electrolytic capacitors on the Scorpio.

I would say that the lamp module, the ABS computer, the EECIV and any other little module on the Scorpio is going to need a
similar going over at some point.

Good thing I bought a big assortment pack of electrolytics at MicroCenter...
http://www.microcenter.com/product/3899 ... assortment

Did you go get yours yet? No? I didn't think so - Let me guess...Your probably one of those lost souls who goes scrounging around hoping
you will find some functional used module in somebody's 20 year old stash that they are hocking on ebay.

You're lost I tell you. You are all lost....

brokencase
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Re: EATC acting up...

Post by brokencase » Fri Aug 17, 2018 9:25 am

Like I said...Failing capacitors in Merkur electrics...biggest challenge going on 30 years...

Below from http://conradhoffman.com/capchecktut.htm

"Everybody wants a rule of thumb for when to re-cap and it's a tough call. I can say from personal
experience that when equipment hits about 30 years old, some occasional cap failures are to be expected.
Sometime between 30 and 40 years old you have a choice- make the measurements and replace as
needed, or do a wholesale replacement on general principle. Many caps will be in good health well
beyond 40 years, but the failure rate will be increasing rapidly for others. One factor that can justify
wholesale replacement is that aging caps will develop excessive DC leakage. Since they have to be
removed for this test, it makes sense to replace them unless they're large and expensive power supply
cans."

Ed Lijewski
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Re: EATC acting up...

Post by Ed Lijewski » Fri Aug 17, 2018 12:25 pm

Looks like you've identified what could be a good side hustle serving the loyal (although diminshing...) Scorpio owners group.

YMMV
Descartes: "Cogito Ergo Sum"
Lijewski: "Sum Ergo Drive-O. Mucho!

brokencase
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Re: EATC acting up...

Post by brokencase » Fri Aug 17, 2018 1:04 pm

EECIV is also vulnerable...but less so. It looks like it only has 3-4 electrolytic caps.

http://support.moates.net/capacitor-rep ... d-a9l-ecm/

I'm going to take this a piece at a time...maybe in this order...

Fuel Computer
EECIV
ABS computer
Speed Control Module
Auxillary Warning Module
Lamp out Module
Warning Chime Module
Antenna Module

Did i miss any others?

Ed Lijewski
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Re: EATC acting up...

Post by Ed Lijewski » Fri Aug 17, 2018 1:58 pm

Blower control module. Might rank high on list.

(Vent door motors have any caps?l

YMMV
Descartes: "Cogito Ergo Sum"
Lijewski: "Sum Ergo Drive-O. Mucho!

brokencase
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Re: EATC acting up...

Post by brokencase » Fri Aug 17, 2018 8:04 pm

Oh yes, let us not forget the blower control module.
I don't think the vent motors have any caps. They are just a motor with a position feedback variable resistor.

I'm not looking forward going through all of these modules. I think I might just do the low hanging fruit first.
Stuff that is easy to get to.

Its a risk trade-off between waiting for some cap to fail and risking it takes out something else out that you can't easily fix, versus
the danger of breaking something while you're in the process of trying to replace caps.

Of course things are further confused by how many beers you've had and if the Phillies are playing.

It's a complicated equation with many variables.

Here's one possible solution to that equation that I think I like...

The only real show stopper in my mind is the EECIV - that could really leave you stranded.

So.. The plan is to buy a cheap used Scorpio EECIV off of ebay. Take that one apart and replace the capacitors in it. If all goes well, I would then have a really good spare.

This is exactly what I've done.

For the rest I can take my time with. I would actually like to dig into the antenna/defrost grid module. I notice that reception is not so good on my HD radio when I have the defrost turned on. Plus I think I could upgrade some components in there to really enhance reception.

For everything else...when i can get to it...or just wait for it to fail.

Ed Lijewski
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Re: EATC acting up...

Post by Ed Lijewski » Sat Aug 18, 2018 12:48 pm

You've got a plan re renewing electronics.

What's your plan re windshields?

YMMV
Descartes: "Cogito Ergo Sum"
Lijewski: "Sum Ergo Drive-O. Mucho!

brokencase
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Re: EATC acting up...

Post by brokencase » Sat Aug 18, 2018 7:15 pm

My glass is Ok. I don't drive on regularly on any highways, So I should be fine.
I'll cross that bridge if and when i come to it.

BTW, I took the antenna module apart, there were two electrolytic caps. I replaced both of them but the old ones
were not too bad according to my tester.

Guess the next low hanging fruit is the lamp module under the drivers side panel.

brokencase
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Re: EATC acting up...

Post by brokencase » Sun Aug 19, 2018 12:23 pm

We should probably re-name this thread "The 30 year old Capacitor Problem"

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