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Advice: 2018 Service Manual Wiring Diagram for SG in error?
I want to add some lighting to my 2018 Sport Glide. I have the factory Service Manual with wiring diagrams. However, it seems the diagram in the manual for the rear lights is not accurate for the SG.
The diagram indicates there are 3 plugs under the seat going to the rear. One plug is for the plate light (40); it has 3 wires going into the plug from the main harness & 2 wires exiting the plug & going to the lamp. That is how my SG is wired.
For the rear Stop/Turn/Tail lamps, the diagram shows each plug has 4 wires entering from the main harness (18 & 19). That is how my SG is set up. It also shows 4 wires exiting the plug, & running into what appears to be an incandescent bulb. That is where the diagram is off for the SG. My bike has only 3 wires exiting the plug, & my lamps are factory LEDs. One of those 3 wires - a violet wire with a black stripe - carries both the signal & brake current. That particular colored wire doesn't show up at all on the wiring diagram. There is also a blue wire (running) & black wire (ground).
Has anyone else noticed this? If I want to wire a 3-wire LED (Ground, Running, Brake), I'm assuming I have to grab the power for the brake function from the wiring in the main harness above where it plugs into the rear harness - is that correct? (The wiring diagram indicates it is a Blue/Red wire).
Main Harness to Rear Harness Rear Harness to lamps
Last edited by Kevinch; Aug 19, 2023 at 09:34 AM.
Reason: Added plug numbers.
What you need to take into account is there is one main wiring loom for all Softail models, thus the rear lighting part of this loom has three plugs with all three having the wiring for the Tail & Stop Light function, this gives the flexibility to use all the different set ups of tail, signal and stop lights fitted to both Domestic & International models.
18A incorporates the right turn signal.
19A incorporates the left turn signal.
40A incorporates the licence plate light.
The colours of the wiring to the indicator/Stop Tail lights themselves are some what irrelevant as it is which pin is used for each function, as too that it appears to show an incandescent lamp rather than an LED as the diagram is just a representation on the wiring layout, if you note it also states on your above diagram of 18 & 19 B, Pin 1, the white wire, is for HDI (Harley-Davidson International) models only so if in the US you will not have or need this wire, thus three rather than four wires.
Regards adding additional lights to these circuits you need to ensure you do not overload them and trip a Diagnostic Trouble Codes as the 'Running Light Power' will set Diagnostic Trouble Code B2619 if 3 amps is exceeded. The 'Stop Light Circuit' B2164 if 4 amps is exceeded.
You may need to use accessory power circuits if the current is too high.
"The running lamps circuit powers up when the ignition is turned on. On HDI models, the running lamp circuit is also
powered in the ACC position. Any running lamp related DTCs will set shortly after the ignition is turned on. DTC
B2169 will set if the running lights circuit is above 3 Amps.
B2164 is set when the stop lamp circuit current draw is above 4 Amps."
Last edited by SJC69; Aug 21, 2023 at 09:05 AM.
Reason: Corrections
What you need to take into account is there is one main wiring loom for all Softail models, thus the rear lighting part of this loom has three plugs with all three having the wiring for the Tail & Stop Light function, this gives the flexibility to use all the different set ups of tail, signal and stop lights fitted to both Domestic & International models.
18A incorporates the right turn signal.
19A incorporates the left turn signal.
40A incorporates the licence plate light.
The colours of the wiring to the indicator/Stop Tail lights themselves are some what irrelevant as it is which pin is used for each function, as too that it appears to show an incandescent lamp rather than an LED as the diagram is just a representation on the wiring layout, if you note it also states on your above diagram of 18 & 19 B, Pin 1, the white wire, is for HDI (Harley-Davidson International) models only so if in the US you will not have or need this wire, thus three rather than four wires.
Regards adding additional lights to these circuits you need to ensure you do not overload them and trip a Diagnostic Trouble Codes as the 'Running Light Power' will set Diagnostic Trouble Code B2619 if 3 amps is exceeded. The 'Stop Light Circuit' B2164 if 4 amps is exceeded.
You may need to use accessory power circuits if the current is too high.
"The running lamps circuit powers up when the ignition is turned on. On HDI models, the running lamp circuit is also
powered in the ACC position. Any running lamp related DTCs will set shortly after the ignition is turned on. DTC
B2169 will set if the running lights circuit is above 3 Amps.
B2164 is set when the stop lamp circuit current draw is above 4 Amps."
Thank you for taking the time to write that all out - it is much appreciated. I've done enough wiring on bikes to have some knowledge - but sometimes it's enough to get me in trouble.
The issue with the aftermarket LED light clusters is there is no information on the amp draw - or information to calculate the amp draw. If I assume an individual single color LED bulb pulls ~20mA (& dual intensity bulbs pull less at lower brightness), I should not be over the threshold of throwing any codes.
I want to add some lighting to my 2018 Sport Glide. I have the factory Service Manual with wiring diagrams. However, it seems the diagram in the manual for the rear lights is not accurate for the SG.
The diagram indicates there are 3 plugs under the seat going to the rear. One plug is for the plate light (40); it has 3 wires going into the plug from the main harness & 2 wires exiting the plug & going to the lamp. That is how my SG is wired.
For the rear Stop/Turn/Tail lamps, the diagram shows each plug has 4 wires entering from the main harness (18 & 19). That is how my SG is set up. It also shows 4 wires exiting the plug, & running into what appears to be an incandescent bulb. That is where the diagram is off for the SG. My bike has only 3 wires exiting the plug, & my lamps are factory LEDs. One of those 3 wires - a violet wire with a black stripe - carries both the signal & brake current. That particular colored wire doesn't show up at all on the wiring diagram. There is also a blue wire (running) & black wire (ground).
Has anyone else noticed this? If I want to wire a 3-wire LED (Ground, Running, Brake), I'm assuming I have to grab the power for the brake function from the wiring in the main harness above where it plugs into the rear harness - is that correct? (The wiring diagram indicates it is a Blue/Red wire).
Main Harness to Rear Harness Rear Harness to lamps
Could you tell me what each color means, pleasse? i.e. running light, turn signal, brake light and ground? thank you!!
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Advice: 2018 Service Manual Wiring Diagram for SG in error?
