Having trouble with my FJ40 headlights - used to work fine, now they won't turn on. All other lights work fine, but the headlights will not come on - have checked wiring, replaced headlamps and connectors... any troubleshooting ideas would be appreciated!
fj40 headlight problems
- Thread starter jeffjoseph
- Start date
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check the headlights switcs.HATTRICK
try replacing the fuse. Mine were all corroded. Next Reseat the connector on the fuse block and then if that doesn't work check the switch with a meter
Jeff;
WELCOME
What year FJ40? How many Miles? Any mods done to said FJ40? When was the last time lights worked? Do u have any books on The FJ40?
Old FJ40's will develop corrosion inside the connectors; spraying same with electronic cleaner will help. You may have disassemble light switch and clean it. All Switches in the FJ40 are fixable up to a point.
WELCOME
What year FJ40? How many Miles? Any mods done to said FJ40? When was the last time lights worked? Do u have any books on The FJ40?
Old FJ40's will develop corrosion inside the connectors; spraying same with electronic cleaner will help. You may have disassemble light switch and clean it. All Switches in the FJ40 are fixable up to a point.
- Thread starter
- #5
It's a 1983 that used to be a bj40 (diesel), but was converted to a fj40 before I bought it. What kind of meter do I need to test the light switch?
Jeff;
Use a VOM [Volt-ohm-miliameter] type meter. U can buy one at RadioSchack or some other electronics store, even home depot. First, learn a little on how to use this test gear. A really big help here is having the schematic (wiring diagram) for the 1983 FJ40. Since this is a converted FJ series, there is no telling what the wiring will really be!!!
In the "Technical Links" of the site are wiring diagrams close to what u need"
i.e.,
http://www.yankeetoys.org/documents/wiring_diagram_78_fj40.pdf
Using the voltage scale, u can measure voltage at the connectors of each light. This will tell u that voltage (around 12 volts) is getting to the lights. However, if there is a lot of corrosion in the circuit, the bulbs will not be getting enough current and voltage to light up. U then need to disconnect the battery and start measuring resistance (Ohms) of the wires back to and thru the switch.
If u are un-comfortable with trouble shooting auto electronics, I would recommend finding some one to help you.
Keep in mind that a BJ40 wiring diagram may not be the same as an FJ40 wiring diagram.
Good luck!
...
Use a VOM [Volt-ohm-miliameter] type meter. U can buy one at RadioSchack or some other electronics store, even home depot. First, learn a little on how to use this test gear. A really big help here is having the schematic (wiring diagram) for the 1983 FJ40. Since this is a converted FJ series, there is no telling what the wiring will really be!!!
In the "Technical Links" of the site are wiring diagrams close to what u need"
i.e.,
http://www.yankeetoys.org/documents/wiring_diagram_78_fj40.pdf
Using the voltage scale, u can measure voltage at the connectors of each light. This will tell u that voltage (around 12 volts) is getting to the lights. However, if there is a lot of corrosion in the circuit, the bulbs will not be getting enough current and voltage to light up. U then need to disconnect the battery and start measuring resistance (Ohms) of the wires back to and thru the switch.
If u are un-comfortable with trouble shooting auto electronics, I would recommend finding some one to help you.
Keep in mind that a BJ40 wiring diagram may not be the same as an FJ40 wiring diagram.
Good luck!
...
Also check dimmer switch. Mine was bad on my 25 and kept both low and high beams from working.
Sounds like someone removed the best part of your truck (the 3B engine) and left you with the "evil centre tap" system, used to run 12 V headlights in a 24 V truck....
Depending on how the engine swap (...and more importantly, the wiring) was finished up, your headlight wiring may resemble a stock '83 FJ-40 (unlikely), a stock '83 BJ-42 (also unlikely -- I doubt the P.O. re-fitted the 2F with 24 V electrics), or some butchered/home-built combination of the two (hopefully, they had a little common sense, and the wiring will be somewhat logical).
You say it's an '83 FJ-40, but originally came with a diesel. That would make it a BJ-42 originally. It would have come stock with a 24 V electric system that uses some fancy/evil tricks to power 12 V headlight bulbs.
If the gasoline swap was well done, you should find (by physically tracing each wire from); the battery(s), through a fusable link (please say the PO used one), through the fuse box, through the headlight switch, which may directly power the headlights, or trigger a relay that powers the headlights.
Regardless of how the wiring was actually implemented, it should at least resemble the above description.
If the wiring was done poorly, you might find some, or all of the original 24 / 12 V system still intact. There have been a few posts regarding the 24 / 12 V headlight sorcery that may help you figure out what WAS there, and at least you won't go chasing down any OLD wiring that is now defunct.
https://forum.ih8mud.com/showthread.php?t=69908
https://forum.ih8mud.com/showthread.php?t=68379
As mentioned, comparing the wiring diagram of a stock FJ-40 to what you have should help in theory, but unless the person who did the work tried to copy a stock system, the BJ-42 wiring for the headlights is vastly different.
If you do find relays (Toyota calls them Dimmer switches) under the dash that are wired to the headlight, are they Toyota parts, or aftermarket? If they're Toyota parts can you read a part number on them? (Don't think you're in the clear if a Toyota Dimmer Switch is labeled 12 V --- the 24 V system has a dimmer that's also labeled 12 V).
Until we figure out how your headlights are wired, you should try the general suggestion mentioned by the other poster. Also, read through the two links above, and report back with what you find. You'll either answer some questions, or find even more, but at least we can go from there...
Cheers,
Steve
btw, If you find any defunct 24 V electrics under you dash, you should box them up, and send them to me for safe disposal
Depending on how the engine swap (...and more importantly, the wiring) was finished up, your headlight wiring may resemble a stock '83 FJ-40 (unlikely), a stock '83 BJ-42 (also unlikely -- I doubt the P.O. re-fitted the 2F with 24 V electrics), or some butchered/home-built combination of the two (hopefully, they had a little common sense, and the wiring will be somewhat logical).
You say it's an '83 FJ-40, but originally came with a diesel. That would make it a BJ-42 originally. It would have come stock with a 24 V electric system that uses some fancy/evil tricks to power 12 V headlight bulbs.
If the gasoline swap was well done, you should find (by physically tracing each wire from); the battery(s), through a fusable link (please say the PO used one), through the fuse box, through the headlight switch, which may directly power the headlights, or trigger a relay that powers the headlights.
Regardless of how the wiring was actually implemented, it should at least resemble the above description.
If the wiring was done poorly, you might find some, or all of the original 24 / 12 V system still intact. There have been a few posts regarding the 24 / 12 V headlight sorcery that may help you figure out what WAS there, and at least you won't go chasing down any OLD wiring that is now defunct.
https://forum.ih8mud.com/showthread.php?t=69908
https://forum.ih8mud.com/showthread.php?t=68379
As mentioned, comparing the wiring diagram of a stock FJ-40 to what you have should help in theory, but unless the person who did the work tried to copy a stock system, the BJ-42 wiring for the headlights is vastly different.
If you do find relays (Toyota calls them Dimmer switches) under the dash that are wired to the headlight, are they Toyota parts, or aftermarket? If they're Toyota parts can you read a part number on them? (Don't think you're in the clear if a Toyota Dimmer Switch is labeled 12 V --- the 24 V system has a dimmer that's also labeled 12 V).
Until we figure out how your headlights are wired, you should try the general suggestion mentioned by the other poster. Also, read through the two links above, and report back with what you find. You'll either answer some questions, or find even more, but at least we can go from there...
Cheers,
Steve
btw, If you find any defunct 24 V electrics under you dash, you should box them up, and send them to me for safe disposal
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just wondering how your project went ?
