86 Elite 150 Deluxe digital Speedo issue. Upon start it cycles

[Gavin S.]

from 100 to 200 and then settles on 0 but does not function as an actual speedo. The odometer is working. Any clues as to what might be the problem. The service manual suggest causes ranging from dead batter to faulty speed sensor but doesn't offer much in terms of how to figure out which one given my symptoms. Thanks for any insight

[flybd5_juan]

from 100 to 200 and then settles on 0 but does not function as an actual speedo. The odometer is working. Any clues as to what might be the problem. The service manual suggest causes ranging from dead batter to faulty speed sensor but doesn't offer much in terms of how to figure out which one given my symptoms. Thanks for any insight

What more do you need? Test or swap the battery, or replace the sensor. Doesn't get any simpler than that.

[Gavin S.]

The battery is good and the service manual lists and entry for the digital speedo but when you scroll down to look for it it is not there so I have no idea where the sensor is and how to test its function.

[flybd5_juan]

If there is any sense to their design, they would follow the same as other scooters they made the same year and put it somewhere in the front wheel.

[Gavin S.]

Touche!

[Johnniespeed]

The speedometer cable drives off the front wheel, it spins a reed switch within the speedometer cluster, the odometer is strictly mechanical.
The reed switch creates a pulse that the digital speedometer reads and translates into MPH.
The reed switch should be able to be tested but not without disassembly of the speedometer unit, the reed switch was originally available as a separate replacemet part, but now has become obsolete.
My best guess is that the reed switch is not creating the correct pulses to the digital speedometer or the actual digital speedometer is receiving the pulses and not computing/ displaying the results.
However before condemning any parts, my suggestion is to carefully measure all the voltage inputs , all the wires, all the grounds, it is more likely some connector is unplugged or a connection is corroded, than an actual part is defective.

[Gavin S.]

The speedometer cable drives off the front wheel, it spins a reed switch within the speedometer cluster, the odometer is strictly mechanical.
The reed switch creates a pulse that the digital speedometer reads and translates into MPH.
The reed switch should be able to be tested but not without disassembly of the speedometer unit, the reed switch was originally available as a separate replacemet part, but now has become obsolete.
My best guess is that the reed switch is not creating the correct pulses to the digital speedometer or the actual digital speedometer is receiving the pulses and not computing/ displaying the results.
However before condemning any parts, my suggestion is to carefully measure all the voltage inputs , all the wires, all the grounds, it is more likely some connector is unplugged or a connection is corroded, than an actual part is defective.

Thank you! That's very helpful!

[4thesporty]

Good information about the digital speedometer.

I am slowly repairing all the POs "creative" wiring on my 86 150D and also have a non-functioning speedometer (with functioning odometer/trip meter).

Mine will partially light up when the key is turned on, but looks to have that "smashed LCD" look towards the middle and does not show anything. Looks like I am going to be looking for a replacement soon.

[4thesporty]

What would cause nothing to show on the digital speedometer?

When I cycle the key on, I can tell the backlight is coming on, but I never get anything on the display. This is on a 1986 elite deluxe.

I purchased another instrument cluster on ebay from an 84 and swapped only the digital speedometer into my cluster and get the same thing. While I had the cluster apart every connector was cleaned up and lubricated with stabilant 22. Of course, the speedometer has it's own harness that plugs into the power block.

Are all bars on the power block powered the same? Could my plug just be backwards and not receiving power?

[flybd5_juan]

I would check voltage on the 12v power wire, and if there isn't any, trace it back to the fuse to see where it is broken.

The plug should only connect one way. If it can be connected more than one way the answer to your question is obvious.