No Dipped lights on my 240z

tjrvp

Club Member
I switched on as usual using the left hand rotary switch , side lights and rears come on, second click no dipped main light.

if you press the high beam flash button on the right hand stalk the high beam comes on. If you then hold the button and pull back the stalk the dipped lights come on. can hear various relays clicking

no amount of switch twiddling can provoke the dipped beam to come on.

Before I tackle the switch, I am tempted for now to wire in a relay to the dipped beams from the side lights.

Any suggestions welcome.
Thanks in advance
Tim
 

jonbills

Membership Secretary
Site Administrator
I wouldn’t switch the headlights from the sidelight feed - a bit gash I think I’d start with cleaning the switch and testing the relay.(If there is a relay?)
 

tjrvp

Club Member
I assumed that switch off cleaning would render the car unusable for a few weeks. I agree its gash but I wanted to have use of the car for now
 

adrianf240z

Active Forum User
Have you checked the fuses first? There is a big feed wire to the switch which should be permanently +. 240 head lamps are wired backwards as lots of other Datsun models of this period are. Normally you turn the headlamps on the power goes to the dip switch then to the main or dip beam then the current returns to the earth side to complete the circuit. Your car has power from the switch sent to the earth pin on the bulb thus making both filaments are live, your dip switch then earths the dip or main filament. Lots of Datsun owners don't know of this circuitry so when trying to fix headlamp circuitry get very confused. I have had several cases of the solder melting on the cable on the back of the switch so the cable becomes disconnected and it needs resoldering. Adrian
 

slaphead

Club Member
Have you checked the fuses first? There is a big feed wire to the switch which should be permanently +. 240 head lamps are wired backwards as lots of other Datsun models of this period are. Normally you turn the headlamps on the power goes to the dip switch then to the main or dip beam then the current returns to the earth side to complete the circuit. Your car has power from the switch sent to the earth pin on the bulb thus making both filaments are live, your dip switch then earths the dip or main filament. Lots of Datsun owners don't know of this circuitry so when trying to fix headlamp circuitry get very confused. I have had several cases of the solder melting on the cable on the back of the switch so the cable becomes disconnected and it needs resoldering. Adrian

Correct me if I am wrong but essentially that stalk effectively provides an earth depending on the position to either dip or main beam, and drags all the current through it unless it's been modified to switch relays instead?
 

Farmer42

Club Member
Unless you have had some form of modification to your headlamp wiring, as far as i know, the 240Z does not have a relay for the dipped beam circuit which is why it apparently fries the wiring if you put higher power H4 Halogen bulbs in. The clicking you can hear is probably the main beam relay.

I had a similar problem a couple of years back and it was a dirty contact on the indicator stalk which operates the main beam (not the button at the end of it which is the flasher circuit and is a separate circuit as stated before). With the headlight switch turned on, pull the indicator stalk towards you and you will feel a click and the main beam should turn on. Pull it again and you will feel a similar click and it should turn off and at that point it should transfer the current to the dipped beam circuit. If you have a dirty contact, it wont transfer the current back to the correct circuit. It might be worth taking the cowl off and cleaning all the switch contacts.

However, it should be noted that none of the main/dipped beam switching works if you don't have your headlights switched on on the other stalk.
 

richiep

Club Member
See Adrian’s last point above - there is a wire under the switch unit that occasionally comes unsoldered and takes the dipped beams out. I’ve had this happen a couple of times - once on the way to Castle Combe in the pre-dawn before 5am! I had to drive with the indicator stalk pulled back until the sun came up enough!

Take the cover off and look underneath the switch - you may well see an unsoldered wire...
 
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