Wiring An FJ40 (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
May 15, 2002
Threads
10
Messages
15
Was wondering if anybody has wired a FJ40? How hard is it.. they make it seem that any body can do it but was wondering how hard it really is..

thanks in advance
 
Wiring is all a matter of opinion. If you have any doubt about wiring, get a Painless Wiring setup. I know they are big bucks, but they fit the factory harnesses (for the most part). Also it depends on what how new your cruiser is, the newer, the more wires. I like to make my own wiring system, that way if something goes wrong with the electrical, I can pinpoint it very quickly.

Some quick tips when doing your own wiring:
1. If possible, always solder your connections. This is way better than cheap crimp connections that can loosen with off-road vibriation.
2. Watch out for pinch points and where the wire will rub/chaff and possibly create a short.
3. Run wires in groups, it saves creating a rat's nest of wires.
4. Finally, heat shrink tubing, electrical tape, and an multimeter are your best friends.
 
I completely re-wired mine from scratch. :D I just could not see paying that much for the painless system. It cost me about $150 and one good weekend. I moved all of the electrical under the hood except for two leads. One for the accessory plug and the blinkers. I put everything in a water ticht box with a fuse block on top (epoxy sealed underneath with a rubber cover). I have a fuse block I can add additional fuses to without too much trouble. I used larger wiring than stock for most of the applications because I had some heat issues, but it may have been related to the old wiring instead of too much current. I used split loom for all runs inside the cab and inside the frame rails to the rear of the truck. I also left several spare leads in the cab and under the hood for future use.

I would make a few changes to the design if I were to do this again to help save space. (I.e runs for brake, running, and turn signals for the rear. I ran too many wires initially.)

I started with a basic layout in mind, wrote everything down and ran one circuit at a time testing everything as I went. My paperwork was detroyed by water in the shop, but I hope to have it all written back down very soon. I can share it once I re-do it if you like.

I have all the stock wiring still in tact, just in case. I am about to remove it though, I am happy with my new wiring and have not had any issues.
 
I completely re-wired mine from scratch. :D I just could not see paying that much for the painless system. It cost me about $150 and one good weekend. I moved all of the electrical under the hood except for two leads. One for the accessory plug and the blinkers. I put everything in a water ticht box with a fuse block on top (epoxy sealed underneath with a rubber cover). I have a fuse block I can add additional fuses to without too much trouble. I used larger wiring than stock for most of the applications because I had some heat issues, but it may have been related to the old wiring instead of too much current. I used split loom for all runs inside the cab and inside the frame rails to the rear of the truck. I also left several spare leads in the cab and under the hood for future use.

I would make a few changes to the design if I were to do this again to help save space. (I.e runs for brake, running, and turn signals for the rear. I ran too many wires initially.)

I started with a basic layout in mind, wrote everything down and ran one circuit at a time testing everything as I went. My paperwork was detroyed by water in the shop, but I hope to have it all written back down very soon. I can share it once I re-do it if you like.

I have all the stock wiring still in tact, just in case. I am about to remove it though, I am happy with my new wiring and have not had any issues.
 
I'm in the middle of wiring mine right now for the TBI motor....figgure I've got about 16 hours in it now and intend to finish tonight.

IMO, plastic loom is much better than heat shrink or taping the wiring. I used heat-shrink wire connectors throughout tho, rather than soldering. IMO, solder is not as vibration resistant (and not as easy...heh)

Wiring is time consuming, and can be irritating. However, once you've cleaned your harness up once, any future work is a breeze....this is my 2nd time thru (first was 5 years ago) and I am SO much better at it....my only issue now is changing the routing of some items and adding in a handful of new circuits.

See my TBI post for some pics of what you can deal with ....heh heh
 
I re-wired mine from sratch as well. I'm running a GM power block from a late model buick that uses Maxi-fuses and a bank of 10 relays. It's nice to have a lot of power sources and lots of relays, especially if you're going to do EFI at some point. I'm also running a small spade-type fuse block in the stock location for just accy items. I soldered everything and ran split loom.
If I were to do it again I would lay out a cruiser size plywood loom with nails guiding the wire bundles. This would also make it easier to make a good wiring diagram.
Cruiser wipers are a PIA to figure out if you don't use the stock switch. I ended up with a mini truck tilt column and it was still a pain.
 
I will soon be running all new wires from scratch and don't really have any concerns except what to do about the connections. I would like to reuse all of the stock ones that way all of the components, i.e. wiper motor, will just plug right in. What did you guys use here????????

Thanks,
Brog
 
I used the stock connectors where they plugged into the old components.
The wiper motor one of the Cruisers strange spots though. IIRC, it runs power to the motor and three grounds back to the switch. Then the switch decides which circuit to complete. Most other apps switch power at the switch and ground at the motor.
I also had park problems because my w/s frame wasn't grounding after the paint job.
 
I think its a great idea to wire the truck yourself, it gives you a far better understanding of where and how things work. Makes trouble shooting in the future a breeze and I would pull the factory conectors off and reuse the plugs. All you need is to make a small tool out of a very small allen key, what I did was grind it down until it would insert into the plugs. Then you push the male or female ends out. Purchase aback of new ones and grimp these with a special tool prior to install.

I like too solder things and then use engineered shrink tube over the connection. Maybe I go over board but I even solder the male or female connectors and shrink tube them with the correct size tubing. There are several different sizes and for them to be effective and shrink and adhear to the wire they must be of proper size.

As for the wire loom, there are many products on the market. I mainly use the plastic style loom and have about four sizes on hand. Its cheap and makes the job look great, at the end of the wires when they end at a plug or some other junction I then tape off the last two inches with electrical tape. This holes the wire in place and gives it a clean look. The factory frame connectors for the wire are OK, I like to use the metal type with rubber cover to insure the wires do not rub through. And to make the job look extra special and be very safe I run the wires all on the inside of the frame. I know what you are think, why run them in the frame where all the mud builds up. First of all I appen up all the drain holes on the frame. And the next thing I do which is tough but worth the time and effort, I drill and suspend the wires midway on the inside of the frame.

Good luck.
Rob
 
That last post of mine was damn long winded, hope I did not bore the hell out of ya.

I forgot to mention a great tip that was given to me by a fellow who I once worked with at ship building company. He did all the wiring and I would stop and admire his work from time too time. His tip to me was when soldering wires together, hold the solder iron againts the wires and put the solder on the opositte side of the wires. This way the wire would heat up enought to suck the solder in. Also do not be afraid to use flux, othrwise you will never get that solder to suck into the wires for a good connection.
 
Thanks for all the replys.. Mine FJ40 is '72 so I think it would be an easier one the wire. I really don't know that much about eletrical wiring so I do a little more research and see if I can do it myself. :)
 
Just about all you need to know there up above. My only addition would be to get a couple feet of fish line(electricians use it to pull wires through conduit or whatever, and they will usually cut you offa couple feet) or get a friend. Electical is great but nothing pisses me off more than spending time trying to run a line through the frame or firewall and it getting stuck or whatever. Also keep in mind extas that you might want to add in the future, now is a perfect time to add a piece of wire than later. Happy wiring
 
how do you know what you really need to wire up and what you can skip....
i am rewiring mine now early 71 for the 2nd time this week
what are the main wires need for the engine compartment??
i got extra wires and dont know where they go

thanks
 
My $.02 is stay with the factory colors on the wires. If you do that you will not have to reinvent the wheel. You can use the factory wiring diagram. If you do any changes or add something to it all you have to do is make notes on the diagram and put it in a safe place for the future.

If you plan to use lights that require more amps you should increase the wire from 14 guage to 12 guage just to keep you from going back into the harness at a later time.

There a 1000 ways to skin this cat. The bast thing is to spend some time and deside what will make you comfortable in the long run.

I just made a new headlight harness for mine last weekend and changed the factory fuseblock. I put in 2 fuse blocks. One is for switched and one is unswitched (always hot). When I do my body switch I plan to build a new harness.

As for connectors the GM style weather packs are very nice but the crimper is big $'s. Good luck.
 
I just finished wiring my 75 40. I also built the wiring harness from scratch using a modern style fuse and the wires that the PO gave me when I bought the thing. I also connected the factory connectors to the new wires. Everything works but the only downside is converting the factory wire colors to the new wires. I copied a wiring harness diagram from my haynes book and documented every time I made a connection. This did two things, helped me remember what I was doing last time I was working and made a reference for me in a few years when I can't remember what is what. I am by no means an expert, but everything works, so good luck!

Zac
 
Where would I be able to find the wire terminals for the factory plugs; I also have a re-wire project coming soon and would like to use the factory plugs.
Thanks
 
AlaskanWheeler try your local Toyota dealer you would be suprised at what you can still get from the factory. The prices are not to bad. I have ordered some parts for my 71. If you get them to order them as shop stock you don't have to pay shipping. It takes a little longer but it will save you money. Money verses time. I know I have more time than money.

If the connectors are in good shap you can take them apart and just replace the pins or spades.
 
I used the Painless, and it's not that different from doing it yourself. Save yourself a couple hundred bucks, and do it from scratch. It will probably take you longer than a weekend if you haven't done it before, but if you study up, and use the same color as the factory harness, you won't have too much trouble. I replaced all of my plastic wiring clips with Deutsch connectors - military grade with a military price, but they'll last forever. It depends on the condition of your harness and connectors, but be careful to remember how to hook everything up - write it down, or better yet, take pictures.
 
I am in the final phase of my PAINLESS wiring harness.
1) make notes of your charging system . Take some pictures. painless instructions on the FJ40 kit are for MOPAR and GM? I have no idea why?
2) same for the amp meter, thats all I have left to figure out.

The painless Kit is for FJ40, Scout, and early Bronco. The directions do not include Toyota, International Harvester or Ford. And when you call the company they will tell you that you bought a universal harness. I bought The fj40 harness from CCOT, thinking it was a FJ40 only harness.
The harness comes with wires for your 4 wheel drive switch and electric fan, but none for your windshield wipers or heater. Very confusing.
Also the painless kit does not come with connectors. I would suggest masking tape and writing down what each connector came from, would have saved me a lot of time.
Alternator and Amp meter kicked my ass, if nothing else write those ones down.

PICS COMING SOON!!!!
 

Users who are viewing this thread

Back
Top Bottom