1972 FJ40 Help- New Jersey

Mar 3, 2012
New Jersey
Hey mud
Looking for some help or advice as to where to seek help. Have a 1972 FJ40 that's been sitting for years, work being done on it every so often. Currently it runs, drives and stops, however there are some things holding me back from getting it registered. The brake lights work intermittently, and the hazards do not work. I've been trying to troubleshoot the electrical problems with a multimeter and everything seems to be functioning as it should, switch is getting power.

Long story short, I'm looking to see if anyone on mud in the Philadelphia/south jersey suburbs would be available to come check out the truck and diagnose my truck's issues. I would compensate you for time and travel. If no one is able to physically check it out, maybe you could suggest a local cruiser mechanic.

Jun 7, 2011
East TN
First thing to check as mentioned above is for good grounds. A long wire lead with alligator clips on each end allows for quick reliable grounding to remove all doubt. You can run it all the way to the battery if you like.
On your 72 the turn signal switch is mostly fed through the hazard switch so poor contacts in the hazard switch could effect the function of your signals.
If you still have the original wiring setup, your brake light circuit is tied in with 2 pressure switches on your brake master cylinder and also with the stop switch activated by pushing on your brake pedal.
The setup I think is to show a warning light on the dash if you are pushing on the brake pedal but not developing enough fluid pressure for the brakes. There are plenty of places for a problem to hide with everything tied together.
Here is the location of the wiring diagram.
FJ40 Wiring Diagrams
The switches are still available from Toyota. I like EB Toyota online, great prices reasonable shipping. If the problem persists you may want to consider replacing those 2 switches and bypassing the pressure switches. The brake switch is easy to check with an ohmmeter if it is unplugged from the harness. It is very difficult (but possible) to replace with the pedal assembly in the vehicle. The hazard switch is more difficult to work on or test.

Good luck.


I can mangle anything ...
Jan 4, 2005
Baton Rouge, LA and Fountain Hills, AZ
hazards are connected to the blinkers, connected to the brake lights, connected to the brake pedal switch, connected to brake fluid indicator light, connected to the handbrake switch - if one but not the other in that system works, you have a ground problem somewhere among those --- [the wiring to the brake fluid switches on the master cylinder can be disconnected without affecting the function of the remaining circuitry]

bad ground is a major problem on these trucks, particularly in rust-prone states

also make sure you have the correct bulbs in the rear - the lights will not function properly otherwise

also, while you are at it (not related to your problem but a current electrical fault source in this vintage): check the high beam switch under the driver side floor - the wires under the truck get mucked up often - take the boot off, clean the connections, install boot again - if there's no rubber boot on the connector anymore, fabricate a cover or wrap in electrical tape
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