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Topic: Trip computer (Read 473 times) |
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Gazza_UK
Full Member
2.3 Ultima auto :-)
Posts: 166
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Trip computer
« on: Aug 3rd, 2009, 11:05am » |
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Was reading on how to reset the MPH and the Average fuel used in the Manual ( yea mine came with one LOL )and No matter what I did it would not reset then I came across this thread
http://www.fordscorpio.co.uk/tripswitch.htm
I did not even know it had LED's in then I looked at this diagram
Now as my RESET was not lit up it also powers the reset switch by the look of it . . .
Any way off to maplins this morning got new LED and YESSSS
I can now reset the trip computer so theres another bit of info for you guys
EDIT
If the buttons dont work is the LED lit
Gazza
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harry.m1byt
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What's YaBB?
Posts: 792
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Re: Trip computer
« Reply #1 on: Aug 4th, 2009, 9:48pm » |
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Whether the LED is working or not, the switches should still work, because the LED's are directly across the +ve and -ve, the latter simply being shared by both switch and LED. What did probably repair your switch was simply opening it up and clearing out the dust which tends to accumulate in them.
A small point on those 12v LED's from Maplins. I enquired from Maplins if they were suitable for the 13.8 - 14.? volts which you can normally expect in a car electrical system. Maplin indicated that their maximum specified voltage from the manufacturer was 12v and that they were not suitable.
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August '95 2.9 12v auto Ultima -
Now flashing 
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amigafan2003
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I'm a YaBB newbie!
Posts: 972
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Re: Trip computer
« Reply #2 on: Aug 4th, 2009, 10:18pm » |
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Quote:| I enquired from Maplins if they were suitable for the 13.8 - 14.? volts which you can normally expect in a car electrical system |
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Actually, that's incorrect. 14v should only be seen directly at the battery - all other circuits should be damped, else you'd see you dashboard lights getting dimmer and brighter depending on the engine revs.
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Gazza_UK
Full Member
2.3 Ultima auto :-)
Posts: 166
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Re: Trip computer
« Reply #3 on: Aug 5th, 2009, 11:10am » |
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Hi Guys
Take a look here the reset switch must go (pass Through ) the little black resistor
this is Multiplexing or some thing like that which means there is 3 or 4 or 5 and so on swirches / contacts on 1 wire and its the resistance which the computer will pick up to see which button is pressed like a keyboard on ya pc there is well over 100 keys on a keyboard but not 100 wires going to a plug. . . hope I explained that right 
If you can zoom in on the circuit board the Neg side of the LED goes through the Resistor possable to power it (12v) and when the switch is depressed you now have another code to tell the computer
Any way I did not clean any contacts all I did was replace the LED and it worked. it could be a fluke tho 
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Tompion
Administrator
1997 2.3 Ultima estate.
Posts: 2918
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Re: Trip computer
« Reply #4 on: Aug 8th, 2009, 7:43pm » |
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Yes just taking it apart will often make it work.
I only have 2 of the LED’s working.
I think the buttons connect one of 3 resistors (depending on which button is pressed) between the negative & the relevant pin of the instrument cluster – the positive is not required & therefore not the LED’s.
I’ve cleaned the switches several times but one of the buttons refused to work for long.
With mine it turned out to be a dry joint on 1 of the resistors.
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ABS multiplug wheel sensor pins MK IV or MK 20
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Ivan Pevnitsky
Full Member
Scorpio Ghia '96, 2.3, Auto
Posts: 172
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Re: Trip computer
« Reply #5 on: Sep 10th, 2009, 12:26am » |
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Does anyone know which LEDs ford uses? At least the manufacturer?
I've bought Kingbright's L-934GD-12V (i think *GT (green transparent, not diffused) would be better, but not in stock nearby, and i'm not even sure if there's resistored modification), wavelenght is 568 nm. But it
seems that it's better to use less wavelenght since 568 is too "yellowed". Unfortunately, Kingbright uses only 568nm for green 12V
Note the difference in colors (click image to enlarge)
PS 2harry.m1byt: Maplins sells Kingbright's LEDs, and according to datasheet for L-1704GD-12V (934's analogue), it's max voltage is 14V
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tlundkvi
Full Member
Ex. Scorpio 2.9 24V -95
Posts: 909
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Re: Trip computer
« Reply #6 on: Sep 10th, 2009, 7:16am » |
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Really hard to even find out, remember these were done ages ago. You can hunt down a used one that's possibly broken except for the leds. Why don't you change the last one also? All switches use different form factor leds, there is no way they can have the exact brightness & wavelength. That is even if the datasheet promises the same (in my experience).
The biggest problem is the to find leds to experiment with. 3mm in native voltage are easy to find, so are 12V leds. But together in the same package, very difficult.
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