Hi to all, I am trying to work out what is wrong with my mothers car, sometimes it starts and other times no crank at all.
tested battery cold 12.15 when it is running 14.35 volts, clean and tight battery connections
all earth points clean and tight [ well the four I could see from the top of engine ] also when I could not start [crank] it, I put a jumper cable clamp on the negative side of the battery then placed the other end on the engine and also tried body grounds but still nothing.
I can hear a click when I try to start it, tested all relays in the box in the engine they all clicked good with power to them also resistance was all the same 0.07, I am not familiar with Toyotas so I could not see a relay with starter on it.
I pulled off the thin wire going to the starter [ guessing it would be coming from the key switch and safety neutral switch [ it's an auto ] put my multimeter in the connection and whilst trying to start it and it read 11.35 volts]
I put a wire from the positive side of the battery to that same connection on the starter and it made the starter fired up.
It can go for days starting up no worries, then out of the blue it starts the no cranking business again.
I have tried to jiggle the auto gear selector up to park and back to neutral but doesn't do anything,
when I put it in to reverse the reverse lights come on, I suppose that is a good sign.
so any help would be greatly received.
thanks

,

 

Got diagnostic work!

A long large electrical cable runs from the battery to the starter solenoid which is bolted to the starter motor. Then a short large electrical cable runs from the solenoid to the starter motor. When the solenoid switch is closed power then runs to the starter motor.

Typically the starter solenoid electrical contacts are the problem. The contacts burn due to arcing and eventually result in a hit/miss, no starter action or a just a click. If an OEM Denso starter the contacts might be available and may be replaceable with starter on the car. This is true for later years but not sure about this year. The contacts look like items in the link below:

https://www.ebay.com/bhp/denso-starter-contacts

A less common issue is the long large cable that runs from the battery to starter solenoid can corrode resulting in low amps to the starter. Your bypassing this cable shows the cable is not the issue.

The solenoid of the starter solenoid is powered by the cars ign switch circuit. Your powering this solenoid directly bypassed the ign switch circuit.

When the ignition key is turned to start. Electrical power from the switch is routed through the trans Park/Neutral switch to the solenoid of the starter solenoid.

The P/N switch can fail, have dirty contacts or bad wiring. Check the black and black/white wires at the switch. Black/white comes from the ign switch, black goes to the starter solenoid. Some owner have managed to take the switch apart for cleaning of contacts.

The P/N switch is a rotary switch. The reverse lights are on a different switch circuit.\

As to what to do. If you bypassed all the large and small wiring from battery and ign switch and still have an issue that comes and goes. Suggest starting with new solenoid contacts if available.

 

Thank you very much for such a detailed answer, soon as I get some spare time I will check as you advised.
many thanks