1989 GL1500 tachometer died.


Information and questions on GL1500 Goldwings (1988-2000)
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YaBoyJB
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Joined: Tue Nov 10, 2020 10:21 pm
Location: United States
Motorcycle: 1989 GL1500

1989 GL1500 tachometer died.

Post by YaBoyJB »



Hi all! My tachometer quit mid ride the other day I checked the wires with a circuit tester. Everything is doing what it should. When I check the red and black wires leading from the board to the needle mechanism they both show the same circuit. Is this an issue shouldn't the black wire be a ground? None of my capacitors appear to be blown or bad so I'm at a loss.



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wingdings
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Location: mells , England, United Kingdom
Motorcycle: Honda Goldwing gl 1989

Re: 1989 GL1500 tachometer died.

Post by wingdings »

Hi - there saw your post there !! - I have a 89k wing also - Try this how to article that should sort it out for you the fella - :D :D :D :D :D :D Just click on the link below !! :D :D :D :D

viewtopic.php?t=2011

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brettchallenger
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Location: Driffield, the East Riding of Yorkshire, England
Motorcycle: 1978 Triumph Tiger TR7 (sold)
2000 Honda GL1500 SE
1985 MZ ETZ250 (a cold war special) - sold
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2018 Suzuki V-Strom 650

Re: 1989 GL1500 tachometer died.

Post by brettchallenger »

Yep, mine died the other week too. So if you can find a way of fixing it, without having to remove the entire dashboard and sending the tachometer off to a specialist, I would be interested to hear from you. Thankfully, it doesn't stop me riding, I rarely look at the gauge but it annoys me it is dead.
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DenverWinger
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Re: 1989 GL1500 tachometer died.

Post by DenverWinger »

The Tach gets its signal from the ECM, tied internally to the spark output for one of the coils. If you have a loss of engine power -only running on 4 cylinders- it's a good bet one of the coil outputs of the ECM has failed. These are repairable, BTW.

If the engine is running normally, check the tach output of the ECM - yellow/blue wire on pin 19. This has a pulsing DC output corresponding to the ignition trigger to one of the coils. Best way to check this is with an oscilloscope. But if you don't have one you can use an AC Volt meter.

With your voltmeter set to AC volts, first measure the volts at your battery. It should briefly indicate some voltage and then settle near zero volts. Some analog meters will not do this and give a False AC volts reading on a DC input. If your meter does this then find another meter.

With the meter set to AC Volts measure the tach output at ECM Pin 19 with engine running. If no AC volts found (I'd guesstimate you'd see at least 2 volts AC, likely higher, depends on the pulse width of the signal) the ECM is likely the problem. If you do get an AC volts reading here, the problem is most likely the tachometer itself, or a connection fault. The Tachometer output from the ECM passes thru connectors C72 and C66 on a yellow/blue wire to get to the Tach.

EDIT - This information was based on the wiring diagram for a '94, should be applicable for 1990-2000 model years. Someone will need to provide the correct info for a '89 model regarding ECM pins, wire colors and connectors, but the test will be the same.
♫ 99 Little Bugs in the Code, ♪
♪ 99 Bugs in the Code. ♫ :(
♫ Take one down, Patch it around, ♪
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brettchallenger
Posts: 970
Joined: Sat May 29, 2010 11:03 am
Location: Driffield, the East Riding of Yorkshire, England
Motorcycle: 1978 Triumph Tiger TR7 (sold)
2000 Honda GL1500 SE
1985 MZ ETZ250 (a cold war special) - sold
2015 Jawa 350 (2-stroke)
2018 Suzuki V-Strom 650

Re: 1989 GL1500 tachometer died.

Post by brettchallenger »

Thanks a lot for this. This will give me something positive to do during this stupid lockdown we have, though I might wait a couple of weeks so my brother (who is a physicist) can come to my garage legally, and we will do it together. I have a decent multimeter so should be able to manage. I suspect the problem to be electrical rather than the meter itself, as it just suddenly went from working faultessly, to not working at all.


“Socialism always begins with a universal vision for the brotherhood of man and ends with people having to eat their own pets.”

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