Now that I’m hopefully getting my 140 really back on the road (I’ve said that before only to be foiled, so here’s hoping) I’m trying to sort out some minor stuff like lights.
So far I haven’t been able to find something that tells me what lights should be on, when.
With the switch in
S position, I have tail lights, and the tiny lights at top of fender, nothing else.
H - same as S, plus headlights. Lower corner mounted lights are NOT on
F - fog/driving lamps, NO headlamps
The lower, large fender mounted corner lights (circled blue in image) seem to strictly be turn signals.
The upper, small fender mounted lights (circled yellow in image) are NOT turn signals.
Is all that correct?
Now, another puzzle and this is kind of sketchy remembering parts of my car are E-type ; the exterior lighting is 100% XK-140, but some of the switches, pedals etc are E-Type…
My brake lights are not coming on… AND the turn signals start slow, and progressively speed up. They’re not LEDs.
Since the 140 uses a single, dual filament bulb, I’m assuming the signal and brake use the same filament, so was wondering if the weird signal could be related to the non-functioning brake light, and if so what some likely culprits might be?
Hi Brandon, your S-H-F lights are working correctly. The turn signals on the XK140 are a little odd since they use the same rear filament as the brake lights. To accomplish that there is a special relay (DB10) that disconnects a brake light from the brake system and connects it to the flasher unit when the flasher is selected. It’s a box the size of a voltage regulator with eight terminals on it.
There are actually two relays and six sets of contacts inside the relay box, and both the brake signals and the flasher signals pass through them, so at the very least you should open it and clean all the contacts.
Brandon,
When your light switch is in the ‘F’ position, you should have the sidelights on as well as the fogs, but no headlamps.
Yes, everything else sounds likely correct, but when my DB10s have failed it’s usually (but not always) one side that fails. Brake light failure could be the hydraulic switch - they’re terrible - but easy enough to check.
Modern repro DB10s are fully electronic, no relays inside. I’ve tried to repair several relay ones with little success.
Slow flashers that speed up are more likely due to an ageing flasher can relay, I’d think. That’s usually mounted behind the DB10 - the photo Mike posted shows a black plastic modern electronic version.
A good tip I learnt when restoring my Cooper ‘S’: Accel make a hydraulic brake light switch for Harley Davidsons which fits right in place of the ‘Lucas’ (which isn’t) unit. It’s much better made, more reliable and lights the brakelights much sooner.
Hi Roger,
That electronic flasher you noticed was supposed to work with low-powered LEDs but it doesn’t, which is why there are two power resistors there to provide a load for it. Right now I am designing an electronic flasher for myself, that fits in the original can and will work with LEDs and with either battery polarity, so I can get rid of the unsightly resistors and plastic flasher.
Making an electronic solid state DB10 that works with either battery polarity would be difficult if not impossible, which is why I was surprised to see this one advertised:
I have an electronic flasher unit for LEDS/bulbs, which seems to work OK and could be fitted inside the original can - it was supplied by Retronics. I gave up on the LEDs eventually as I had no end of problems with the single pilot indicator lamp. I ended up with wires and diodes everywhere…
