All,

I just put into my car a Tach, which works just fine. Taped off the old wire for the clock so as not to damage anything with it just hanging there and then tucked it away in a wire bundle. The little clock however does not work and I will delve into that later as it is getting power but no movement.

My question is this. I noticed that my "Check Engine" light does not come one when I turn the key to position II even though I checked the bulb and it does work.

I also know that it goes to/from the ECU (3.1) through a pink/white wire, however how does it get there? Am I missing something? I have replaced both wheels for the odometer about a year ago, so did I miss something when putting it back together?

Thanks,

Matt

Alright, I now believe the PDF for the wiring diagram for the 1991 is WRONG! Surprise, Surprise!

I say this as I just ohmed out the connection and where it comes out, it is attached to red & white wire, or at least it looks that way to me.

The wiring diagram calls out connector 235 as pink & white. Mine looks red and white. In fact it looks exactly like my Tach wire, however it has a different end connector to thus you could never by accident attach the tack to this light.

Any one have any thoughts on this?

I'm gonna put it all back together minus the tach and minus the clock and hook it all back up and see what I get. If it now works, then I'm putting the tach back in as before and hooking all the wires back up.

Wish me luck!

Matt

Hi Matt,

Sounds like you're working from the Mitchell drawings.

"Taped off the old wire for the clock so as not to damage anything with it just hanging there and then tucked it away in a wire bundle. "

Huh?

The pink/white is as you describe it, the only such wire with a male faston. Terminal 235 on the back of the cluster is a female. The only female. So, no, you can't get them mixed up without some hanky panky.

The lamp test should be available from both ECU and ICU. They are wired together (wire or-ed in EE parlance) so the lack of lamp test on CEL is doubly concerning. I'd even go so far as to suspect a PO hiding a CEL from you (or the Maryland Vehicle Emissions Inspection Program) by unpinning or cutting at the ECU, ICU or both. Yes, a conspiracy theory actually holds more water here than the theory Mitchell copied the drawings incorrectly.

I would not trust my color receptors to distinguish 25-year-old red dye from 25-year-old pink dye. In fact, that I am male, restricts me to knowing only those 12 colors you find on resistors -- you know the rhyme I'm sure.

If you never see the CEL come on, you need to chase this down, because some day it will come back to bite whomever drives that '91.

Here are some (slightly) better maps.




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Art Benstein near Baltimore

A chicken crossing the road is poultry in motion.

Art,

Thanks for the drawing, and yes, I was wrong about the colors. The manual was correct.

I looked at it again today after work and it is pink, though a light shade and at quick glance, it appeared red.

I put it all back together tonight and all is well in the world.

Now on to dismantling the clock so that I can replace the capacitors inside. Going to dismantle one of my larger clocks so as to steal the caps from as I don't want to wait for anything from digikey. Just like to get this thing back up and running.

Thanks again for all your help. You are the man of knowledge!

Matt

One thing you might consider... the caps you take from a working large clock are apt to be only slightly less dried out than those you are considering replacing in the enclosed small clock. They are necessarily of the same era. Some Radio Shacks still remain in business, right?
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Art Benstein near Baltimore

I'm late getting in on this...you had an un farad vantage.

"Some" being the ultimate word! IF they are in business, and IF they have them.

It's a unicorn that I'm trying to find.

You are correct about the capacitors. Same era, same amount of dryness.

May have to reconsider this in my haste repair this thing.

I've already had one set back this morning. I'm having a hard time getting under the rolled lip to try and pry it back so I'm going to cut a small piece of the black trim where it is rolled in order to create a better surface with which to get a prying device under. Thus I now have time to go to Radio Scrap and inquire if they might even carry and/or have in stock such unicorn capacitors.

I'll let you know how I fair. I'll check tonight actually and if they don't have them, then DigiKey it is!

Later,

Matt

Matt,

There should not be anything unicorny about 100-microfarad radial lead electrolytics. I realize as an EE you know the voltage rating is just a maximum, so anything above 15V will do, but include this just in case someone else finds this thread despite it being about check engine lights. I suppose "CEL" is the more-often searched term.
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Art Benstein near Baltimore

I think you guys should pull the plug on this thread.
On second thoughts, that would be a volt-face...

Art,

What I meant about Unicorny is Radio Shack actually carrying them yet! They might, but I'm not holding my breath.

I have one right around the corner from house in Eburg. Will check it out tonight on the way home.

Matt

Right. They used to. Not that I personally verify, but I've been in a lot of clock repair threads, so that's what I hear from others who have already been through this. Whether they do now or not is a phone call or a visit. That Eldersburg store is the link I provided in my previous response. The stores by me are shut, I think. Yes, selling piece parts at a retail store doesn't sound like a business plan with a future. We should be seeing more "maker" resources as the emphasis on STEM continues in education.
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Art Benstein near Baltimore

"Don't know what you do for a living but I am always wary of measurements made by people who only infrequently must do and use precision measuring tools...sorry but the right touch is something that takes practice--and honesty about our potential role in inducing or seeing error.. " -John V

The RS near me did have the caps I needed.

I just finished rolling the lid off, so I'll finish it in the morning.

Enough for one day.

Matt

Unrolling the front bezel was something I learned here on the Brickboard. I had posted about my approach, using a Dremel to score the can, and a long-time member pointed out the bezel is hidden by the plastic, so mangling it didn't matter.

Good advice, as the heat in the dashboard (and from the light inside the clock I suppose) softened the adhesive on the aluminum HVAC tape I used to reassemble the can.

<--click on the thumbnail.
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Art Benstein near Baltimore

My sister would enjoy these. I'll contact her and relay them.

I got some caps from RS over a year ago. Any electronic supply houses near you?
Dan

"Any electronic supply houses near you? "

None I'm aware of. There's Baynesville electronics (or used to be) but that's a goodly journey one might combine with Harbor Freight -- they're in the same relative area, and nothing I do is so urgent I can't wait for Mouser, Digi-key, or ebay. Those last-minute things were what RS did well.
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Art Benstein near Baltimore

Where the circuit breaker for this re-volt-ing thread?

I have a Harbor freight almost around the corner, where there used to be a RS. The last RS I went to was about 10 miles across town.

I purchased some relays from Mouser to fix my Kenmore oven a few years ago. Lots cheaper than a new oven or even the control board replacement!. Thanks to Google and someone else with the same problem.

Dan

Coincidentally, two weeks ago today, I worked on a daughter's oven control board. Thought of it as a first pass, as she said it would just cut off mid-baking, throwing a code for temp sensor, and then a general code.

Her husband had already swapped in a new sensor without changing the symptoms. About the only thing I could have seriously done with the thing would have been replace relays, not finding any visual evidence. He mentioned the board's cost would make a replacement oven a viable alternative. Don't recall the brand, but they said it was 7 years old.

Only one solder joint looked even the slightest bit iffy, but it was the one to the terminal where the temp sensor connected. Hail Mary, reflowed it and a few others where possible temperature stress might occur. Since then, she is bringing us baked goods and trying to expand my belt line. If the failure recurs I'll be sure to check Google. And Mouser. Thanks.
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Art Benstein near Baltimore

I just thought I'd zap in and relay my disgust at these puns.

My Kenmore was doing the same thing. Chances are with an older unit someone else has delt with it already and posted the solution.
Dan

I'm all for repairs, major or minor but I'm sure someone can find you a clock in GWO if things don't work out.

"...but I'm sure someone can find you a clock in GWO..."

Nah. This is one area where a repair is necessary because those that might appear to be in "GWO" are so only on a warm day, unless they've had those capacitors replaced. They all need this done.
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Art Benstein near Baltimore

Can't you people conductor serious conversation?