The K100 wiring diagram, Bert's troubleshooting guide and the HES manufacturer all have apparently contradictory information on them.

The HES guide http://www.hallsensors.de/CYHME56C.pdf shows red as +12 volts, black as ground and green as output. This is in agreement with the OEM 2AV54 HES datasheet https://datasheet.octopart.com/2AV54-Honeywell-datasheet-92379.pdf
The two HES sensors I have in front of me which were taken off a defunct unit are wired as follows:

- both red wires from the sensors go to black in the K100 loom
- both black wires from the sensors go to orange in the K100 loom
- green from the lower sensor goes to red in the K100 loom
- green from the upper sensor goes to brown in the K100 loom

If that isn't confusing enough,

- Bert's diagram shows signal outputs on pins 2 and 5, power on pin 3 and ground on pin 4 (viewing the socket from the input, non-wire side, I assume)
- The actual loom on the bike has power on pin 5 (red), ground on pin 3 (black) leaving signal outputs on 2 (brown) and 4 (orange), (viewed in the same direction as the plug on the HES lead i.e. from the wire side of the plug on the loom and with the pins numbered in the same direction as Bert's)

So... all this means that on the HES,

- both red wires (positive) from the sensors go to black in the K100 loom which is ground
- both black wires from the sensors (ground) go to orange in the K100 loom which is a signal wire
- green (output) from the lower sensor goes to red in the K100 loom which is +12 volts
- green (output) from the upper sensor goes to brown in the K100 loom which is (finally) output to signal

That... doesn't make a huge amount of sense. The only conclusion that I can draw is that I do not understand the status/usage of the wires as they emerge from the ICU and head off down to the HES and that the colours are not exactly ...erm... standard in their use.

Charlie? Rob? Can you throw some light on this mess please?

Watch it, there has been a change in colors in the wires over the years.

I don't really follow the connector pinning, I do understand the power wire (red and black) going through the HES units are to ensure the trigger fires up the orange and brown wires though. Maybe ignore the connector and follow the wires and double check that orange and red combo they must have faded.

The five pin connector has the bottom pin as a shield pin and the top two as red black power throughput. the middle two show the orange to be on the left coming from the loom and browny/greeny sort of colour on the right, of that the upper hes unit goes to the left or orange side.

Do you number that connector from top left to right and then down left to right and bottom the shield pin??

ive got a spare changed set  around here Dai 

ill take a pic for you 

but what your saying doesnt make much sense at all 

i woud have thought the red and black were the power input wires to the hes  the centre wire out of each hes is the signal 

anyhow pic coming in a sec

just remembered i put the last reco set into the 85 motor that i got recently 

but did take pics of the pull down before and after replacement 

seems that the orange is the common negative 

the black is the common positive 

red is the far sensor signal (shortest (botom sensor ) off the cable ) brown ? is the longest (or top ) sensor lead off the cable 









hope that helps ?

It confirms I'm not being stupid anyway. Laitch raised a good point in a PM; did you need to add the pullup resistors to the Chen Yang sensors? I've assumed a like-for-like replacement, but assume has probably made an ass out of me and they are needed. Gonna try it myself in a couple of hours.

I don't know if this helps, but its a pinout of the HES plug under the tank on a 2v

This is where the problem originally hit. The wire colours do not match their expected functions and I really dislike BMW for doing this.

Black is crimped to the red sensor wires (power)
Orange is crimped to the black sensor wires (ground)
Red is crimped to the bottom sensor green (output) wire
Brown is crimped to the top sensor green (output) wire

It's only when you remove the sensors from the plate you can see this. See Charlie's pics.