Electrical Gremlin(s) ???????

[HarrisBikeNut]

Just returned to the UK from a two up tour of SW France with Caday Rouge motorcycle tours. Fantastic roads and views, great riding and a VERY comfortable base with good food, swim pool and fantastic peace and quiet. My 2018 Tri Glide was, overall, fantastic. Plus points were comfort (DK 14” shocks and lift plates fitted) more than adequate performance (bike has a Stage 1 kit fitted), superb luggage capacity, enjoyable to ride and handled everything thrown at it over 2,700 miles. Negatives? Not the most economical at motorway speeds, physically hard work on mountain roads after a full day, spending time telling people about the bike!!!

However, after 5 days, I lost rear lights. Red light on dash showed up, fault code displayed which cannot be reset so clearly a fault that is present not historical.

Today, I have checked continuity of the wiring looms from each rear light unit and the two other wiring loom parts that eventually connect to a grey multi pin plug under the rear of the seat. No issues with any of the wires including the blue wire that powers the rear lights. So my question! Could the BCM be at fault? I should add all other lights work, as well as indicators, brake lights, etc.

Any forum members had a bad BCM that displayed similar issues?

Also, a final question please! Can the heat from the engine “overheat” the BCM and cause it to “misbehave”?

TIA

Bob

[Old Road Dog]

Have you checked the lamp bulbs? What was the fault code? Do you have any added accessories like luggage rack lamp etc. Perform a "wiggle test" at that gray connector. Move and bend the wires and see what happens. Separate the connector halfs and check the pins and sockets. Tug on the wires and see if they have come loose from the pins/ sockets.

[Jack Klarich]

Have you checked the lamp bulbs? What was the fault code? Do you have any added accessories like luggage rack lamp etc. Perform a "wiggle test" at that gray connector. Move and bend the wires and see what happens. Separate the connector halfs and check the pins and sockets. Tug on the wires and see if they have come loose from the pins/ sockets.

Present the fault code that cannot be reset, how are you scanning for codes?

If you are scanning thru the radio, you may not see all the other codes

Follow this link,

https://www.appletonhd.com/harley-da...trouble-codes/

Highly unlikely your BCM is bad, the trouble code (s) should tell you where the fault lies

[Old Road Dog]

Buddy of mine retired as a HD parts guy. Said 99% of ecm/bcm's sent in as bad actually tested good. As far as heat there are thousands of HD's running around Arizona and Nevada where in the summer its hot enough to burn the hair off the back of a tortoise- no problems.

[Jack Klarich]

Buddy of mine retired as a HD parts guy. Said 99% of ecm/bcm's sent in as bad actually tested good. As far as heat there are thousands of HD's running around Arizona and Nevada where in the summer its hot enough to burn the hair off the back of a tortoise- no problems.

Good point, also if a BCM or an ECM were bad you would most likely get a U code = no communication

[HarrisBikeNut]

This is the code - “B2168 Running lights output shorted low”

I am scanning by holding down the “trip” button on the left switch gear before switching on the ignition and then scrolling through. The B2168 cannot be cleared suggesting to me it is a current fault.

Bike has genuine Harley heated grips, a Jims Forceflow fan, genuine heated seats connected with genuine connectors as per Harleys fitment sheet. These were all fitted some time ago.

The rear lights are LED’s (?) so no bulbs to check. Rear lights are stamped indicating which pin is what. That shows me the blue cable (power to running lights) is where the fault is. Continuity checks out and since I have indicators and brake lights all three other wires must be fine. Once I reach the large grey plug the loom moves under the tank - as yet I haven't removed the tank to check in the plastic channel where the wiring looms run forward.

[Old Road Dog]

I understand you have continuity but do you have voltage on that blue wire? In multi strand automotive wire, one good strand can show continuity. A DVOM with back probes is the tool to use now.Also, by making a jumper wire with molex pins/sockets you can bypass the harness wire and connect directly from the gray connector to the lamps. Did you do the wiggle test?

[Jack Klarich]

I understand you have continuity but do you have voltage on that blue wire? In multi strand automotive wire, one good strand can show continuity. A DVOM with back probes is the tool to use now.Also, by making a jumper wire with molex pins/sockets you can bypass the harness wire and connect directly from the gray connector to the lamps. Did you do the wiggle test?

The rear running lights are also tied to the front running lights

There is a wire harness that runs from under the gas tank forward that has been reported to be too short and pinched wires can cause a problem with rear lighting

One test would be to turn on the ignition, sweep the handle bars full stop both ways, see if the lights flicker

[Old Road Dog]

OK got to my diagnostic manual- here are the probable causes: Running lights circuit resistance to low. Short to ground in running lights circuit. Accessory lighting overloading circuit. Rear running lights circuit test: turn ign off. disconnect rear running lights.cycle ignition off-on.Did DTC reset? No? Repair short to ground or high current draw in the running lamp circuit of the rear lighting harness. Repeat test for front running lamps.

[HarrisBikeNut]

Thanks for the replies gentlemen! Appreciated!!

Will try the suggestions made today. Don't have the meter mentioned or the relevant pins etc but lets see what transpires.

Bob

[HarrisBikeNut]

Right, tried to fixes offered -

Moved handlebars side to side - no signs of flickering rear lights

Disconnected grey plug under rear of seat to disconnect rear lights. Cycled ignition, reconnected with no change. However, I noticed when I tried to clear the code using the method previously described I can hear a distinct noise (almost a squeak) from somewhere forward of the battery etc. Is this normal? After disconnecting the grey plug, these fault codes appeared

B2151 Left rear turn signal output open

B2156 Right rear turn signal output open

Understandable as they had been disconnected but the codes were cleared with no strange noise…..

If time permits, I will remove the tank and have a look but this noise seems odd to me…….

Bob

[Old Road Dog]

Are you sure the squeak you are hearing isnt the fuel pump cycling on? "They all do that"

[HarrisBikeNut]

Are you sure the squeak you are hearing isnt the fuel pump cycling on? "They all do that"

Definitely NOT the fuel pump. Nowhere near as loud. Just been out to check and repeated some of the suggestions.

[Jack Klarich]

Definitely NOT the fuel pump. Nowhere near as loud. Just been out to check and repeated some of the suggestions.

Compression release activating?

[HarrisBikeNut]

Never heard of it but why would it operate with the ignition off when clearing fault codes?

[Old Road Dog]

Sayyyyy.....do you have a security siren on that bike?

[Koolbreeze]

Do you have a set of regular bulbs that you can put in to replace the LED ones in the rear light? You said you do not have a volt ohm meter, so if you can't test you can check by putting standard bulbs in the sockets and see if the fault code clears.

[Jack Klarich]

Never heard of it but why would it operate with the ignition off when clearing fault codes?

When you have the ignition on is it cycling the compression releases?

[Jack Klarich]

Sayyyyy.....do you have a security siren on that bike?

Do you have the Fob present?

[1dn5up]

Electronics

Stupid suggestion but worth a try . Disconnect the battery for a while .