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TR4/4A headlight switch TR4a
- Thread starter Richard_Brown
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Rrbbeerrttoo
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No, neither pass or driver flasher work with ignition off, they flash only with ignition on run, at least on TR4a's. What seems really strange to me is that stop lights do not work either with ign. off.
Robert
Robert
Rrbbeerrttoo
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If one needs to , anything can be easily changed to be "ON" with the switch off..just have to consider fuse loads.
Robert
Robert
TR3driver
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That seems to have been the European custom at the time, I've had cars from Germany & France that worked the same way. After having an American car where the brake lights would sometimes come on by themselves (and run the battery down), it seemed like a good idea.Rrbbeerrttoo said:
But I still used unswitched power for the TR3 brake lights, as I wanted them as bright as possible.
Rrbbeerrttoo
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TR3driver.
"But I still used unswitched power for the TR3 brake lights, as I wanted them as bright as possible"
What did you mean by this statement?
Robert
"But I still used unswitched power for the TR3 brake lights, as I wanted them as bright as possible"
What did you mean by this statement?
Robert
TR3driver
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Er, what do you mean, what did I mean? I was re-engineering the brake light circuit on my early TR3 to have 3 functional brake lights instead of only 1. And since I know there is always a little bit of voltage lost going through the ignition switch, I opted for a separate fuse fed directly from the control box.
TR3driver
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Rrbbeerrttoo
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Randall,
I am new in forum language. I now understand , should have known unswitched meant by-passing ignition switch. Your car has bright tails lights, almost too bright for the car following you. Did you also change bulb wattage from the original Tr3?
My Tr4a taillight brightness shows insignificant difference with the 0.2 volt drop ( approximate , per 260 Simpson VOM ) measured at the fuse block, versus at the voltage regulator.
Thanks. Robert
I am new in forum language. I now understand , should have known unswitched meant by-passing ignition switch. Your car has bright tails lights, almost too bright for the car following you. Did you also change bulb wattage from the original Tr3?
My Tr4a taillight brightness shows insignificant difference with the 0.2 volt drop ( approximate , per 260 Simpson VOM ) measured at the fuse block, versus at the voltage regulator.
Thanks. Robert
TR3driver
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Ah, I see, sorry for the confusion.
Yes, those are also higher output bulbs, model 2357. The wattage is only about 5% higher than the usual 1157 bulbs, but they are also optimized for more light output (at the expense of shorter filament life), so the light output is about 25% greater. But they look and fit exactly as original.
But they are nowhere near blinding, the camera exaggerated the brightness to some extent.
Incandescent bulbs are very sensitive to operating voltage. 0.2 volts is only about 1.6% in voltage, but it reduces the light output by some 5%. Still not a huge difference, maybe I'm just a little obsessive
Yes, those are also higher output bulbs, model 2357. The wattage is only about 5% higher than the usual 1157 bulbs, but they are also optimized for more light output (at the expense of shorter filament life), so the light output is about 25% greater. But they look and fit exactly as original.
But they are nowhere near blinding, the camera exaggerated the brightness to some extent.
Incandescent bulbs are very sensitive to operating voltage. 0.2 volts is only about 1.6% in voltage, but it reduces the light output by some 5%. Still not a huge difference, maybe I'm just a little obsessive
Rrbbeerrttoo
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Randall,
Thanks, that clears everything up.
Robert
Thanks, that clears everything up.
Robert
richie
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So about these top two wires (N & NU) that control flash to pass... How exactly is this activated? After bench testing my TR4a switch for continuity, I couldn't figure how these 2 lighter gauge wires interacted with each other or the 3 other thicker gauge wires (power, parking lights, headlights).
Is my switch broken or am I missing something?
TR3driver
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I don't have my 4A owner's manual handy, but as I recall you pull the stalk towards you to flash the headlights. That connects the two wires together; which should supply current to the selected beam if the ignition switch is on. As Don noted, the operation is somewhat different than later cars.
According to the diagram, the N wire gets fed by a GN wire that runs from A4 on the fuse block. It should be hot when the key is on (and the fuse isn't blown).
Oddly enough, the factory diagram shows that the output of the flash switch is a UW. Do you perhaps have one of those? Anyway, the output from the flash switch should be joined to the main headlight output (U) and the wire to the dimmer switch.
According to the diagram, the N wire gets fed by a GN wire that runs from A4 on the fuse block. It should be hot when the key is on (and the fuse isn't blown).
Oddly enough, the factory diagram shows that the output of the flash switch is a UW. Do you perhaps have one of those? Anyway, the output from the flash switch should be joined to the main headlight output (U) and the wire to the dimmer switch.