I spent some time disconnecting everything one at a time to document the symptoms; this is what I found. Please let me know if I missed anything significant so I can add it.
Glow Plug/Starter Relay Link: Power for GP system and Starter solenoid
No GP relay click when ignition is placed into the ON position; when switched to the START position single starter relay click but engine doesn't turn over/crank.
IGN. fusible link: Switched power for the ON & START positions
No GP relay click, no starter relay click, shutoff solenoid is not energized (diesel/no fuel), no temp or fuel gauge readings, no warning lights, no radio/clock.
LIGHT fusible link: un-switched power for lighting and horn
No cabin/door or external lights. No hazard lights, but turn signals work. No PRN lights, but the warning lights do illuminate. No radio/clock, radio/clock memory lost. No horn.
ALT. fusible link: disconnects alternator
Single GP relay click, starter relay clicks but engine doesn't crank/turn over. Weak/dead battery. Surprisingly, it does not cause the alternator failure indications (maybe if it fails while running?).
Lock, DEF., and AC, fusible links:
Door locks, rear defrost, and AC disabled as indicated.
Start Solenoid Signal Wire Connection: Not really a fusible link, but in the same area
Everything seems normal, GP and Starter relays do energize/click as normal, but starter does not engage
**Note that the fusible links in the picture are the replacements I make/sell... the colors are different from the OEM ones (grey instead of green, and blue instead of red). On some L300's the LIGHT fusible link is lighter duty (green instead of red).
Downloadable PDF Copy
Glow Plug/Starter Relay Link: Power for GP system and Starter solenoid
No GP relay click when ignition is placed into the ON position; when switched to the START position single starter relay click but engine doesn't turn over/crank.
IGN. fusible link: Switched power for the ON & START positions
No GP relay click, no starter relay click, shutoff solenoid is not energized (diesel/no fuel), no temp or fuel gauge readings, no warning lights, no radio/clock.
LIGHT fusible link: un-switched power for lighting and horn
No cabin/door or external lights. No hazard lights, but turn signals work. No PRN lights, but the warning lights do illuminate. No radio/clock, radio/clock memory lost. No horn.
ALT. fusible link: disconnects alternator
Single GP relay click, starter relay clicks but engine doesn't crank/turn over. Weak/dead battery. Surprisingly, it does not cause the alternator failure indications (maybe if it fails while running?).
Lock, DEF., and AC, fusible links:
Door locks, rear defrost, and AC disabled as indicated.
Start Solenoid Signal Wire Connection: Not really a fusible link, but in the same area
Everything seems normal, GP and Starter relays do energize/click as normal, but starter does not engage
**Note that the fusible links in the picture are the replacements I make/sell... the colors are different from the OEM ones (grey instead of green, and blue instead of red). On some L300's the LIGHT fusible link is lighter duty (green instead of red).
Downloadable PDF Copy
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