Fuse lebeling bat 15 amp burns out - 2000 Harley Davidson FLHR-FLHRI Road king

If the brake switch wire is melting, there is an issue with the size of fuse supplying it.
Check there is no short circuit on the rear clusters.

Have you tried changing bulbs? Usually one low beam burns out and you really don't notice so when the second one burns out it looks like a serious problem. There is no fuse for the headlights if it's not the bulb the next thing to check is the dimmer switch. I hope this helps. Take care.

if it doesnt blow right off the bat i would say fan motor drawing too many amps stateing you have correct amp fuse ussually at least a 20.if yes id replace fan motor.common on this automobile.

Fuse 42 should be 15 amps-not 10. If 15 amp fuse still burns, Brake light circuit is drawing too much current, causing the fuse to burn. The problem may be the shift lock solenoid or the lights. See diagram at link below.
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=122871

For headlight fuse blowing on dyna,click the link below:----http://repairhelpcenter.blogspot.com/2012/01/headlight-fuse-blows-on-harley-davidson.html
---------Thanks.

www.digi-key.com or www.newark.com stocks those fuses.

Have you checked the fuse box under the driverside dash? If memory serves it should be a 15 to 25 amp fuse. I would suggest you check all of the fuses with a fuse tester. And take a close look at all the grounds.

FUSE USAGE

1. 10 AMP LOW BEAM-LEFT
2. 10 AMP LOW BEAM-RIGHT
3. 30 AMP BRKR POWER WDO/SUNROOF
4. 30 AMP BRKR PWR ACSRY
5. 20 AMP BRKR LIGHNG CONTROL MODULE
6. 15 AMP IGN/REM ACSRY CONT/INST CSTR
7. 10 AMP SUPPLEMENTAL INFLATABLE RST
8. 20 AMP CORNERING LPS/TURN SIG
9. 10 AMP CRANK SIGNAL-SIR
10. 20 AMP TRK REL/FUEL FILL REL/BACK-UP LPS
11. 15 AMP BAT/RADIO/PWR ANT/CIG LGTR/ INST CSTR
12. 20 AMP ELECTRONIC LEVEL CONTROL
13. 20 AMP BRAKE & HAZARD LAMPS
14. 15 AMP PARK LAMPS
15. 15 AMP COURTESY LPS/PWR MIRRORS
16. 10 AMP COOLING FAN
17. 25 AMP HEATING/AIR CONDITIONING (C67)
18. 15 AMP A/C AUTOMATIC ELECTRONIC (CJ2)
19. 10 AMP ANTILOCK BRAKES
20. 10 AMP LOW COOLANT/LAMP MONITOR
21. 10 AMP IP LIGHTS
22. 10 AMP HI BEAM-RIGHT
23. 10 AMP HI BEAM-LEFT
24 10 AMP IGNITION/RADIO
25 25 AMP WIPER/WASHER

FOR ACCESS TO ADDITIONAL FUSES
REMOVE RIHT SOUND INSULATOR

Your fuse panel is located by the emergency brake.Depress the two tabs and the fuse box will swing down, the panel diagram is written on the panel door.

the machine is pulling to much power.check to see if it is on a 15 or 20 amp outlet. you said you replaced the fuse. the amp size should be on it. if it is a 15 amp fuse,plug the machine into a 20 amp circuit and see if the fuse blows then. it shouldn't since it wasn't blowing everytime on the 15 amp circuit, but never put a 20 amp fuse in a 15 amp socket! the fuse can handle the load[ no pun intended], but the electrical wire would burn not blowing the fuse, thus causing a fire.
hope this helps.
wg