Hi all,
I have a problem with the above on my Series IV Sunbeam Rapier fitted with a D Type OD. I cannot road test the car as it's not yet road legal here and so all the test are carried out in the garage but assume the electrical functions are not dependant upon the overdrive actually running.
There is a supply to the relay via the isolator switch on the gearbox which is funcioning OK ie switching off when 3rd or 4th are disengaged.The column switch does not operate the overdrive on or off,the warning light does not come on at any point and there is no sign of the relay operating.I have checked the wiring is correctly connected to the relay and column switch and so I can only assume therefore that the fault lies with relay,although I have tried a spare the result is the same with each. How can I test the relay for function and does anyone have any suggestions as to what the problem could be.
John
Overdrive relay
Re: Overdrive relay
Testing a relay is very easy, if you put your meter across the switched pins (30 and 87) then supply 12v to the coil pins (85 and 86), your meter should show no resistance. when you remove the voltage, it will go open circuit.
Handy diagram of a relay here:
We will definitely have some members that will be able to offer some insight in to overdrive operation, personally I have never owned an overdrive car so can't help with that bit I'm afraid.
Handy diagram of a relay here:
We will definitely have some members that will be able to offer some insight in to overdrive operation, personally I have never owned an overdrive car so can't help with that bit I'm afraid.
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.
Re: Overdrive relay
Hi Terry,
Thanks for very rapid reply.The relay is a 1960's design and bears no resemblance to modern relays,which I am familar with,but I do have a schematic diagram of the old type and I'll see if I can work out which terminals are which and then test as per your explanation.
John
Thanks for very rapid reply.The relay is a 1960's design and bears no resemblance to modern relays,which I am familar with,but I do have a schematic diagram of the old type and I'll see if I can work out which terminals are which and then test as per your explanation.
John
Re: Overdrive relay
You can buy a split new replacement that looks exactly as the original. THESE stock them and they are identical - in terms of what they do - to the more modern relays, but the pin numbers may differ as Lucas built thae things before the tags were standardised. 
J
"Home is where you park it", so the saying goes. That may yet come true..
"Home is where you park it", so the saying goes. That may yet come true..
Re: Overdrive relay
Hi John,
I've now isolated the problem it's a faulty column switch. I know it's impossible to find a new replacement and would imagine it's not practical to
try and repair the switch. I wonder if replacing the column switch with a 'momentary on' type toggle switch would be an option.My thoughts are that the column switch only operates when depressed and switches off when released.Any input would be appreciated.
Regards
John
I've now isolated the problem it's a faulty column switch. I know it's impossible to find a new replacement and would imagine it's not practical to
try and repair the switch. I wonder if replacing the column switch with a 'momentary on' type toggle switch would be an option.My thoughts are that the column switch only operates when depressed and switches off when released.Any input would be appreciated.
Regards
John
Re: Overdrive relay
Have you had a look? lots of older switches are completely repairable. there is a good chance it is just dirty contacts. If you can get the switch out you could see if it can be dismantled, clean the corrosion / dirt from the contacts and put it back together.
You could also try squirting contact cleaner in to every gap in it then flicking it on and off a few dozen times then test it again.
I have fixed the wiper switch in my mog with the contact cleaner method, and the headlamp column stalk on my last RR. Range Rover seat switches are cake to take apart and clean, I must have done 20 of them.
You could also try squirting contact cleaner in to every gap in it then flicking it on and off a few dozen times then test it again.
I have fixed the wiper switch in my mog with the contact cleaner method, and the headlamp column stalk on my last RR. Range Rover seat switches are cake to take apart and clean, I must have done 20 of them.
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.
Re: Overdrive relay
Thanks for that Terry,
It's not prcatical to remove the switch from the column casing as some numpty has fixed it in with a sort of 'plastic padding' type putty which has set rock solid and I suspect attempting to remove it will break either the switch or the casing.
I'll have a go with the contact cleaner method.If it doesn't work what do you think about the 'momentary' switch option? I could fit it in a convenient place and leave the column switch as a dummy.
Regards
John
It's not prcatical to remove the switch from the column casing as some numpty has fixed it in with a sort of 'plastic padding' type putty which has set rock solid and I suspect attempting to remove it will break either the switch or the casing.
I'll have a go with the contact cleaner method.If it doesn't work what do you think about the 'momentary' switch option? I could fit it in a convenient place and leave the column switch as a dummy.
Regards
John
Re: Overdrive relay
Thanks to those who contributed.
I've now sorted the problem,it turned out to be the switch wiring which had been incorrectly connected by a previous owner who soldered the wrong wires to the wrong terminals.
Regards
John
I've now sorted the problem,it turned out to be the switch wiring which had been incorrectly connected by a previous owner who soldered the wrong wires to the wrong terminals.
Regards
John
Re: Overdrive relay
That's frustrating but at least you have it fixed.
A previous owner of my RR had cut the wiring to the sunroof / rear wiper in 2 places. That stumped me after swapping fuses, relays and both motors I finally found the problem after removing the headliner.
A previous owner of my RR had cut the wiring to the sunroof / rear wiper in 2 places. That stumped me after swapping fuses, relays and both motors I finally found the problem after removing the headliner.
Understeer: when you hit the wall with the front of the car.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.
Oversteer: when you hit the wall with the back of the car.
Horsepower: how fast you hit the wall.
Torque: how far you take the wall with you.