Hi I'm new to the fj40 and this forum. I bought a 72 fj40 and the headlights won't turn on,but all the park light turn on when I pull the headlights switch could this be the dimmer switch on the floor board or the headlight swith it self?
headlights won't turn on
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Here's my fj40
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Welcome to IH8Mud!
Could be the dimmer switch, the headlight switch, or even two bad headlight bulbs. Use a jumper wire from the battery + terminal to the Red/Green and Red/Yellow wire on the back of the headlight connectors to verify the bulbs are good. The headlight will light when either wire is jumpered to hot. If they are, check that one of the three terminals , (B Terminal) has +12V or more on it when the headlight switch is pulled all the way out. If it does, but still no headlights, then it's the dimmer. If it doesn't then it's the headlight switch. Good luck!
Could be the dimmer switch, the headlight switch, or even two bad headlight bulbs. Use a jumper wire from the battery + terminal to the Red/Green and Red/Yellow wire on the back of the headlight connectors to verify the bulbs are good. The headlight will light when either wire is jumpered to hot. If they are, check that one of the three terminals , (B Terminal) has +12V or more on it when the headlight switch is pulled all the way out. If it does, but still no headlights, then it's the dimmer. If it doesn't then it's the headlight switch. Good luck!
I'm having a similar problem with my 1980 fj40. The running lights work but the headlights do not. I bought 2 new headlights and they going work. I checked and the fuse is good. Detailed info or help?
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Could be the dimmer switch, the headlight switch, blown fuse or a bad ground. Since you have new bulbs you can probably rule them out.
Start with the simple thing of checking the 15 Amp headlight fuse. If that is good, pull the head light switch out of the dash and verify you have +12V on the large red wire going into the 6 pin headlight connector. If you have +12V, then pull the head light switch to ON and verify you have +12V on the Red/White wire on the 6 pin connector. If you do the head light switch is good. Re-install switch and move on to the dimmer. There will be a 6 pin connector under the dash going to the steering column. In that connector will be the Red/White wire from the headlight switch which should have +12V when the headlight switch is on. This goes into the dimmer switch in the column. The dimmer switch sends that +12V to the Red/Green wire in that same 6 pin connector which goes out to the head light low beams or the Red/Yellow wire in that same 6 pin connector which goes out to headlight high beams. If all that checks out but still no headlights then it has to be the ground to the headlights. This ground is located in the headlight connectors on the back on each headlight. It is the White/black wire. Turn on the headlight switch then run a temporary ground from the battery - to the White/black wire one one of the headlights if they light up you will need to start looking at the harness for white/black wires that are not attached to the body. There are two, one on the drivers side inner fender and one that grounds under one of the fuse block mounting screws.
Good luck!
Start with the simple thing of checking the 15 Amp headlight fuse. If that is good, pull the head light switch out of the dash and verify you have +12V on the large red wire going into the 6 pin headlight connector. If you have +12V, then pull the head light switch to ON and verify you have +12V on the Red/White wire on the 6 pin connector. If you do the head light switch is good. Re-install switch and move on to the dimmer. There will be a 6 pin connector under the dash going to the steering column. In that connector will be the Red/White wire from the headlight switch which should have +12V when the headlight switch is on. This goes into the dimmer switch in the column. The dimmer switch sends that +12V to the Red/Green wire in that same 6 pin connector which goes out to the head light low beams or the Red/Yellow wire in that same 6 pin connector which goes out to headlight high beams. If all that checks out but still no headlights then it has to be the ground to the headlights. This ground is located in the headlight connectors on the back on each headlight. It is the White/black wire. Turn on the headlight switch then run a temporary ground from the battery - to the White/black wire one one of the headlights if they light up you will need to start looking at the harness for white/black wires that are not attached to the body. There are two, one on the drivers side inner fender and one that grounds under one of the fuse block mounting screws.
Good luck!
This is a really good troubleshooting description Coolerman. I copied it and will be putting it in my FJ40 journal.
My experience with the pre-73s is its usually the dimmer.
Interestingly enough, I ran all the tests Mark suggests on a buddy's '73 about 20 years ago without success (IH8 electrical) in frustration, we built a replacement loom. When we went to plug it in to the backside of the fuse panel, we found the terminal was corroded!
So add that to the list of things to check.
Best
Mark
www.marksoffroad.tripod.com
Interestingly enough, I ran all the tests Mark suggests on a buddy's '73 about 20 years ago without success (IH8 electrical) in frustration, we built a replacement loom. When we went to plug it in to the backside of the fuse panel, we found the terminal was corroded!
So add that to the list of things to check.
Best
Mark
www.marksoffroad.tripod.com
Check the large connector under the passenger side dash for dirty contacts.
I'm going to try everything tomorrow. Pictures with instructions are always welcome. I'm quite new at this but will attempt everything even if it means breaking my nails lol
There's a large connector on the wiring harness under the passenger side dash. Pull it apart and clean out the contacts. Maybe give it a good wiggle and see if the lights turn on.
Is this the car for a right by hand drive vehicle?
Going to work on it tomorrow. I'll let you know.
k old thread here. looking to have some one (@Coolerman ?) confirm i have a bad dimmer.
i have a 1972 fj40
when i pull the light switch all the way out my marker lights come on but no headlights.
when i jump my headlights (red/green post on the headlight) both lights come on so bulbs are good.
fuse is fine
with the lights on there is no power at any of the three terminals on the dimmer
red/white off the back of the light switch has power when the switch is on.
i just would have thought i’d have power at the red/white terminal on the dimmer if i have it on the back of the light switch. am i missing something here?
i have a 1972 fj40
when i pull the light switch all the way out my marker lights come on but no headlights.
when i jump my headlights (red/green post on the headlight) both lights come on so bulbs are good.
fuse is fine
with the lights on there is no power at any of the three terminals on the dimmer
red/white off the back of the light switch has power when the switch is on.
i just would have thought i’d have power at the red/white terminal on the dimmer if i have it on the back of the light switch. am i missing something here?
Sounds like a corroded connector terminal somewhere on that red-white wire.
that’s my thought too the more i think about it. my son reminded me that they’ve never worked from the day we bought it. i was so confused before he told me that as the only way i could put that all together was some break in the wire but it’s one area of the harness i haven’t touched. i couldn’t figure how i could have caused that. anyway i think i have the culprit now. i’ll try jumping the dimmer to that post and see if things work. that’ll confirm it’s the wire/ connectors
amazing how little corrosion (and i mean barely visible) it takes to mess with this circuit!!
next is getting rid of these screwy motorbike signal lights!!
next is getting rid of these screwy motorbike signal lights!!
That’s because 12 volts is a very small amount of electromotive force
yep. i’m thinking i might wire in a relay so the power to the headlights isn’t all going through the switch. especially if i go to a halogen or higher power bulb.