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weak dash circuit


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I've been wondering why my dash clock is extremely dim for a while, and just a while ago I honked the horn, and it is extremely weak too. They are on the same fuse, so it seems like that whole circuit is getting very low voltage or current. Any ideas how? Also when I pull the fuse out the engine dies, what else is on this circuit?

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I've noticed the same thing with my '92 Loyale... the dash clock goes rather dim or out completely intermittently. A little research when I was putting a new deck in revealed that the clock, radio, hazard lights, horn (IIRC) , and automatic seatbelts are all on the same circuit.

 

Unlike you, however, I haven't noticed any problems on the rest of the circuit when the clock display is dim/gone.

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http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=397DFB0F.31F6%40mit.edu&prev=/groups%3Fq%3Dsubaru%2Bclock%2Bdim%26btnG%3DGoogle%2BSearch%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8

 

W. Curtiss Priest, Director, CITS

Center for Information, Technology & Society

466 Pleasant St., Melrose, MA 02176

Voice: 781-662-4044 BMSLIB@MIT.EDU

Fax: 781-662-6882 WWW: http://www.CyberTrails.org

 

 

Technical Note

July 24, 2000

 

1980-1992 Subaru Automobile

 

Repairing Intermittently Displaying Car Clock

(Flourescent green digital display style)

 

1988 Model DL

2 Wheel Drive

1800 cc

Single Point Fuel Injection (SPFI)

 

 

Preface: these repair notes are written for those who would rather fix it themselves than purchase car repairs.

 

And, if you've collected enough electrical parts, you can often do these repairs without leaving home!

 

Also, when you take into account the time spent bringing a car in for repair and either waiting, or having to arrange other transportation, you are often ahead in time, doing it yourself.

 

I do get occasional notes from mechanics at Surbaru garagesabout why I would want to do this when the part is "only" $$.

They forget that they need only walk over to the parts counter and spend your money on parts that cost many times the original manufacturing cost.

 

***

 

This particular repair is very quick when you know what to look for. You need not even disconnect the clock, so access is about 10 seconds.

 

Total repair time is less than ten minutes.

 

***

 

Symptoms:

 

1. clock display goes dim or out

2. pressing one of the setting buttons may cause display to return

 

Repair:

------

 

Clock pops out of dash, lightly prying side

 

Remove 4 wires from back clip.

Remove cover, prying slightly on clips.

Unsnap PC board prying slightly on one of two side clips

 

Inspecting board:

----------------

 

Solder around power resistors looked "cooked" -- I shook off loose solder by heating and tapping the PC board on the dash.

 

I checked for tinning on resistor leads. These looked good, I resoldered, and there was no change in the problem. (probably a good idea to resolder these anyway)

 

Flexing board caused display to change brightness.

 

Problem and Repair:

------------------

 

The 150 ohm 1/2 watt resistor to the left of the buttons had a poor solder connection to the circuit trace running to the buttons.

 

I resoldered that end of resistor. Clock got bright, no amount of board flexing changed it. Clock was fixed.

 

Amusing:

-------

 

So, the reason the clock got brighter when an hour, minute, or second button was pressed was because this flexed the board, causing the 150 ohm resistor to "reconnect" due to the mechanical flexing.

 

In Case You Wanted to Know:

--------------------------

 

The reason there are four wires running to the clock is:

 

1. Ground

2. Battery voltage for when ignition is off

3. Battery voltage for when ignition is on

4. Battery voltage for when you switch on parking or head lights

(this causes the clock to be dimmer at night !)

 

=============================

 

Al's addition:

I had to resolder an area on the left side of the board, too, to fix mine.

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As to the weak horn issue. Check the electrical connections at the horns themselves, looking for that nice green color. Found that to be the problem on both of the BRATs. You need to clean the connections if you find them corroded. Going to try that clock repair myself, as both clocks don't keep time when I shut off the key.......

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All fixed. There were 3 HEAVILY corroded solders, and about 8 broken solders (hairline cracks)!! Works fine now, though when I resoldered the power wires, it was dark in the car, and I accidentally switched the yellow with the red :rolleyes: So the light stayed dim as if the headlights were on. So I had to redo that. Contacts on horns are good, not going to pursue that further tonight.

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I don't know, I've never seen one. Is it LCD, LED, or electroluminescent?

 

I've fixed other digital dashes (mostly Fords). But I've heard that some of the GM ones are impossible.

 

You did see that I didn't write that stuff, I was only repeating it, didn't you?

 

A cursory search via Google reveals that that unit's speedometer has a cable just like the non-digital dash, up to the back of the cluster.

 

Strangely, very few people are complaining about the early Subaru digital dashes -- I found only about four posts on dead or dying ones.

 

It'd be a lot easier if I had the car as well as the dash, but if you're willing to ship me the cluster, I'm willing to look at it. I've had pretty good luck with other automotive electronics.

 

ZIP 98368

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I had an 83 Touring Wagon with a digital dash... at some point the speedo display started to work intermittently, ie. the two digits were dead (black), or it was working perfectly!

Everything else worked fine.

 

Eventually it was replaced with another cluster on which some of the trip computer fuctions weren't working correctly.

 

Seeing as someone has also mentioned Fords and GMs, apparently Nissan's digital dash was problematic too. Similarly the fix was to re-solder some dry joints on the circuit board.

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  • 2 months later...

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