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My 1968 MK 340 won't start using the switch inside the car on the dash. A recent phenomenon in past 3 months. One push of the button on the solenoid under the hood does the trick, but that's a pain. Otherwise runs great. Should I replace there button starter on the dash, or??
You need to find the problem before you start throwing parts at things.
Connect a test lamp to the solenoids terminals and see if 12 volts is getting to it when the STARTER button is pushed. (you may need a helper or have long wires running from your test lamp)
If the test lamp lights, then assume it's the solenoid itself.
Run 12 volts to the solenoid, it should start the car, if it does not, replace the solenoid.
Also look for bad connections from the starter switch inside the car to the solenoid.
MAKE SURE IT'S OUT OF GEAR AND THE PARK BRAKE IS ON.
Do the test Jeff suggested. It will tell you if the problem is the solenoid or getting 12 volts to it from the dashboard button. If the latter, it may be a bad contact in the button. That's often fixed by giving the black button a twist.
You need to find the problem before you start throwing parts at things.
Connect a test lamp to the solenoids terminals and see if 12 volts is getting to it when the STARTER button is pushed. (you may need a helper or have long wires running from your test lamp)
If the test lamp lights, then assume it's the solenoid itself.
Run 12 volts to the solenoid, it should start the car, if it does not, replace the solenoid.
Also look for bad connections from the starter switch inside the car to the solenoid.
MAKE SURE IT'S OUT OF GEAR AND THE PARK BRAKE IS ON.
Thank you, I'll try the 12v light test and post again
If all else fails buy yourself a new starter button. They are readily available & cheap. Mine had become erratic so I fitted a new one ~ they don't last forever.
No not necessarily. You are manually forcing the solenoid to make contact against a spring. That does not tell you if the solenoids wiring has burnt out to activate it. (pull it into contact) when the dash button is pushed.
Last edited by Glyn M Ruck; May 24, 2022 at 08:10 AM.
Jose the "solenoid" under the bonnet is a switch activated by a solenoid. In other words if you push the rubber capped button on the solenoid it is the switch you have activated. The solenoid inside is operated by a small current initiated by the starter button and once the solenoid is engaged the switch allows the starter to activate. So if the starter button on the dash is not sending the small current down to operate the solenoid then the car will not start from starter button on the dash.
This is also why on an Automatic which has an isolation switch for the gearbox can still be started from under the bonnet via the rubber capped button on the solenoid even when it is in gear as the gearbox isolation switch only stops power going to the dash button.
Thanks everyone for their input, bottom line after researching, purchasing and temp. install of new $9 starter button, faulty wiring. My mechanic said thank you for stopping before "breaking" something and installed a new 10-way switch. Front left fog and horn were also "problematic" and all fixed now. I bought a 1973 TR6 new and drove it almost 100,000 before selling so I've encountered Lucas electronic previously. I worked on it during those years tuning (adjusting dual side draft Stromberg's, tuning, changing all fluids including the rear "wet shocks", doing brake work and clutch work so I know/knew a bit about English cars. I like to try to suss what is going on and when I saw just two thumbscrews dropped the entire dash I was like a kid in a candy store. 50 years on now, I know when to stop before I really BREAK something so that's when I got an appointment at my GREAT Jaguar restoration/mechanic.
btw, my 1968, LHD has a Heritage Certificate and all numbers match. It was first delivered to Belgium but around 2012 brought to the US by a colonel in the US Army in 2010. It has 87,000 km and a 4sp manual w/ OD. It was repainted, glass out in 1988 the original old English white and except for hoses, other rubber e.g., engine body mounts, filters, shocks, clutch, and brakes all original as it came out of the factory. Given it's light use and care there is no under body or for that matter any surface rust, all lighting and gauges work tho' the speedo does "dance a bit after around 60 km/hr and the radio wont pick up US stations.
Starter switch or solenoid?
