Bad ignition switch?

77ToyFJ40 · May 15, 2025

Trying to start my fj40 for the first time after getting my carburetor rebuilt and it won't turn over. I have 12v on the wire coming from the battery but nothing everywhere else on the starter. I tried ohming out my ignition switch. I have ohms on both right side pins but not the left side I also have ohms on the top two pins but not the bottom. Is the switch bad?

charliemeyer007 · May 15, 2025

Put it in neutral, set the brake. Key on and use a crappy screwdriver to jump the solenoid and see if it cranks. Inside the solenoid is a big copper washer that transmits the power when energized - The washer can get pitted from the arc and corrode up. I dressed mine with file - cranked right after that. I had an ignition catch fire once. Dust/metal filings build. Took it apart and cleaned it to get home. Bought an new switch. Headlight switch did that too.

77ToyFJ40 · May 15, 2025

charliemeyer007 said:
Put it in neutral, set the brake. Key on and use a crappy screwdriver to jump the solenoid and see if it cranks. Inside the solenoid is a big copper washer that transmits the power when energized - The washer can get pitted from the arc and corrode up. I dressed mine with file - cranked right after that. I had an ignition catch fire once. Dust/metal filings build. Took it apart and cleaned it to get home. Bought an new switch. Headlight switch did that too.

I haven't tried jumping the solenoid yet but I've checked for power everywhere. I have power at the coil but it's not consistent. Sometimes I have 12v other times I have 6 or 7 volts. I don't seem to have switched power at the solenoid. I put my meter on the solenoid while my wife turned the key all the way and there was no power.

CruiserInProgress · May 16, 2025

It seems like you may have some connection issue somewhere. Were there any connectors that you touched during your carb rebuild? If so, start there.

If you don't get 12v on your solenoid while cranking, that's not right. But, it could be caused by various reasons. One of which could be the ignition switch, but not the only possible cause. There are a lot of other connections in that circuit.

When trying to get my 79 going, I went through and cleaned all important ignition connections, including battery posts, frame and engine grounds, and all relevant ignition circuit connections (coil, igniter, starter, cold start circuit from starter to coil +).

About the variations in voltage on your coil + terminal, 12v sometimes and 7v sometimes is expected on a system that uses a resistor circuit to feed the coil. When current is flowing through that resistor (or resistor wire) only 7v will be delivered to the coil +, so that it doesn't burn coil, points or igniter.

But for starting, a full 12v is needed to make starting easier. On the 79, that 12v comes from the starter when it's cranking via a jumper wire.

Your model may be different, but it sounds like you do have a resistor in the ignition circuit. Check your coil + when cranking and see if you have 12v.

Still, I would go through and clean all your connections. Time and corrosion can create weird issues with your electrical system.

Then start checking voltages again.

45Dougal · May 16, 2025

How do the wires look in the back of each connector?
You can easily get corrosion on those crimps.
The switch is simple to test - of its not making contact then it's either the switch, the wire, or the crimp.

77ToyFJ40 · May 17, 2025

I finally got it to crank yesterday. There was a bad ground coming from the starter.

CruiserInProgress · May 17, 2025

77ToyFJ40 said:
I finally got it to crank yesterday. There was a bad ground coming from the starter.

Yeah, those FJ40 grounds can be problematic. Glad you found it.

I like to clean them well with some fine sand paper (avoid steel wool), then use a bit of dielectric grease on the connection to preserve it.

ToyotaMatt · Jun 7, 2025

77ToyFJ40 said:
I finally got it to crank yesterday. There was a bad ground coming from the starter.

it is good you pin-pointed the need for a good solid NEG - Earth grounding current to the starter motor ,,,,,,

your 1977 FJ40 rolled of the PLANT A11 assembly line with what's called a CABLE BOND No. 1 ,
examine the tech. photos below , i think you understand the importance of making this and that as it was new in 1977 ...
i often get folks asking me , " how come my Land Cruiser did not come with one or how come it does not have one ? " ...
well ....
i do know why and know the only why-factor involved that made it disappear as your 1977' 's factory installed original one has experienced the same exact fate ....,.

- the 1962 - 6 / 83 Land Cruiser starer motors were the size-spec of a loaf of Martin's Wonder Bread , and the inside electrical technology was designed before Man Landed on the Moon ( July 20, 1969, at 20:17 UTC ) and remained un-changed till it's modern update was now factory installed and also quickly found its way onto the 1962- later all F series Engine's .....However , this information on being able to saddle a newer Gear Reduction starter , was not spoked about by Toyota , as they still kept offering there Dinosaur DENSO Loafs of Bread up to till 2016 ...
the older starter design is a Single Reduction direct drive motor to the the star drive gear shaft , there life expectancy of single digit years less then 5 was a accepted normal thing ....
each new replacement starter install required the removal , and then re-install / re-use of the CABLE BOND No. 1 , the starter side Ring Terminal was Soft Yellow Brass , and got all F'ing twisted up from the Jurassic-size thick spring washer biting down on it and taking it for a twisting force clock-wise ride , the same thing occurred upon removal of the old starter too via counter clock-wise twist and bite ....
so ....

when the stater got replaced more then 2-3 times , in a short amount of time , that Brass Ring Terminal would eventually die , and nobody at the time late 1970's - 1980's had or kept any form of the CABLE BOND No. 1 in-stock , and that includes the toyota dealers too ,...

No Toyota Dealership service dept. or a private shop was going to tell a customer they had to order this part from the dealer , and wait a few days and be out of there Toyota to drive as well .
'

So what i saw go on at the Toyota Dealership when this did occur in the late 90's and 2000's was the Technicians simply zapped out the M8 bolt at the frame rail location where it secured the other end of the Cable Bond No. 1 and that is how and why some Toyota's Cars , Trucks and Land Cruisers do not have any sign one was ever there ,,,,,.
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note ; i never once did this because i always had a pocket full of the 6AWG w/ 1/2 " hole pep-boyz getto-grade cable end lugs in my box , this way i could repair it on the spot during a starter install , and get a extra . 4 flat rate hour in my pocket at the end of the week just like that ... :idea:

photos of a factory installed original still in place and the SCARY Size-Spec. Bread Loaf Starter motor too .........
/

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Below is my Reproduction CABLE BOND No. 1 in action .... bigger cable 2AWG , verses the Punie and weak 6AWG that was used back then ....
Tin Plated Solid Copper Lug Ring Terminal ends are OEM ANCHOR marine grade = heavy duty tough as nails ... ( these will never twist and de-form )
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