1971 Body/Chassis FSM

1971-74 F Engine FSM

Page Index


Last updated 11-09-2005

Rear Turn/Brake Lights

Since I had replaced the rear cross member with one from a 1974 (See Section 11) I now had to use the newer 3 way tail lights with separate turn lights. I got a used set from Tim Jones in Odessa, Tx for a VERY good price. He even sent me an extra pair of housings! I took the best two housings, stripped out the electrical stuff, sandblasted them then gave them two coats of rust bullet. I then rebuilt the electric harness. See below for the transformation from horrible to serviceable.

Rear Lights


Now that I had them protected it was time to address the rust holes ...

Rusted Housing

Fig. 2

I used a fiber glass repair kit to patch the holes in the housings (See Fig. 3), then put another coat of rust bullet on them.

Patched Housing

Fig. 3

Polished Old Lenses

Fig. 4

Polished Old Lenses

The lenses Tim sent ,while not broken, were very faded and scratched. but had no cracks. I used rubbing compound and lots of elbow grease to polish them. They turned out looking like new ones!  See Fig. 4. In case you are wondering why I didn't use the Dremel tool? Even at low speed it would melt the plastic!

I put the lenses up until I could get a set of gaskets. There is plenty of other work left to do believe me!

Isolating the Brake Switch from the Turn Signal Switch

Harness Mods

Fig. 5

Brake Harness Mods

The stock 1971 FJ40, like a lot of older American vehicles, uses a single two element bulb to provide four functions: Park Lights, Brake Lights, Emergency Flashers, and Turn Signals. One element is used for the park lights and the other serves the other three functions. The newer 1974 and up FJ40's used a separate turn signal light to meet European lighting specs.

So how do we make the old system work with the new? It's actually very simple to accomplish. In a nutshell all we have to do is isolate the brake switch from the turn signal switch, run a new wire from the isolated brake switch connector back to the new brake lights then connect the left and right turn signal wires to the new separate bulbs. Just in case someone (the next owner? ) wanted to put the wiring back the way it was I cut the wire from the brake switch connector under the dash and crimped a male connector on the connector side and a female connector on the other. Then when I ran the new brake wire I crimped a female connector to it. To put it back to factory wiring all that has to be done is unplug the new wire and plug the other two back together. See Fig. 5.

Isolating the Brake Switch from the Turn Signal Switch

  1. Disconnect the battery! Failure to do so WILL result in lots of sparks!
  2. Take the instrument cluster loose and then disconnect the speedo cable. Fold the cluster forward or remove it. Referring to Fig. 5 locate the large white 4 pin connector coming from the brake switch.
  3. Cut the wire shown and crimp on a female bullet connector to the connector side and a male bullet connector to the other side.
  4. Run a 14ga wire from here to the rear of the truck. Crimp a male bullet connector to this wire. Now you can go back to stock wiring simply by unplugging the new wire and reconnecting the factory wire. For now of course you are going to connect the new wire to the switch. Connect this wire to each of the brake lights. Now when you hit the brakes the power comes from the fuse box to the switch, through the switch down the orange wire and to the lights. It no longer goes through the turn signal and hazard switch.

New Wiring Harness

Since my stock harness was sort of non-existent I had to create a new one. I located the old harness running down the right frame member and cut it back to good wire. The wires in the stock harness are as follows: a * indicates that this is a new wire.

Wire Color
Old Function
New Function
Park Lights
Park Lights
Backup Lights
Backup Lights
R Turn/Brake/Emergency
R Turn/Emergency
L Turn/Brake/Emergency
L Turn/Emergency
* White
* Orange
Brake Lights

The old combo lights relied on the housing being grounded through the mounting bolts. As we all know this 'ground' tends to fail once rust sets in resulting in intermittent lights. Toyota provided a separate ground wire to the light housing on the new style lights to elimnate this issue.

Finding stock Toyota connectors can be difficult so I decided to just use a newer style automotive connector that is weather proof. I used the Delphi Packard Weather-Pak connectors . These can be gotten from several places in 2,3,4,5,6 pin versions. I got mine from Waytek Wire.  I used a 4 pin version that resembles a trailer connector. I should have gotten a 5 or 6 pin version because I forgot about needing a ground! I ended up using a bullet connector to provide this.

New Pigtail

Fig. 6

New Plug

Matching Socket

Fig. 7

Matching Socket

New Harness

Fig. 8

New Harness


To build the new harness I cut the old connectors off of each light and attached the new male plugs. See Figs. 6- 7. Next I laid out enough wire to reach everything to make up the new harness. I had to use different colors of wire but I drew up a schematic so I will know what is what. I soldered the wires to the old harness and used heat shrink tubing to seal that. Using 1/2" wiring loom, some cool loom 'T' connectors and 3M splice taps with dielectric grease, I designed a harness that is better than the stock harness. See Fig. 8 for a section of it.  The hard part was the Park light circuit. That one wire has to power 5 bulbs in the rear of the truck! Two side markers, two rear lights and one License Plate light. I used the splice taps to make these connections. When used with dielctric grease these things rock! Fill the connector with the grease, place it over the wire, crimp with pliers, crimp a standard 1/4" spade connector to the wire you are connecting, fill the spade connector with grease then just plug it in! Instant water proof connection. Make sure to wipe off excess grease so it doesn't attract dirt.

Stock Harness

Fig. 9

Early Stock Harness Layout

Next up: 71 to 74 cross member conversion





1971 Body/Chassis FSM

1971-74 F Engine FSM

Page Index

Hosted by Global Software, Inc.

©1998 - 2023 Mark C. Baker Web Designer

Please: No part of this web site may be used without express permission... email mbaker@globalsoftware-inc.com for permission.