Hazardous undertaking. Need help with lights

I have finally gotten front and rear flashers to work. The red light on the panel flashes. Are the green arrows in the dash supposed to flash also? Cause they are not

the a pillar flasher can works on the bench.

I have no directionals. Which fuse/color wire do I power up to check directionals. I put 12 volts to all of them and got nothing.


I only have the rear lamps hooked up, do I need all 4 lights hooked up to get directionals to work? Seems unlikely, in the old days a bulb out just gave you a faster flash or a steady no flash IIRC


You mean the hazard warning flasher (based on your topic title) right? If so, on my 1967 S1 OTS, flipping the hazard warning flasher only pulses the hazard panel red light. It does not trigger the green directional signal lights.

I can’t see from my meager electrical knowledge how it could light the directionals, as the hazard switch supplies its own power for the lamps. The directionals draw their power from the flasher unit, and how they could be powered by the hazard switch escapes me.


The blinker can includes half of an RC circuit. Resistors and capacitors and time create the switching. The resistors are the lamp filaments themselves. That’s why the blink rate changes or fails when lamps are in or out of circuit - you need all four. The blink rate on my E was way too low when at idle - no contribution from the 25A genny so I changed a capacitor in the can to increase the blink rate.

My E is too old for hazard lamps. My Morgan, however, has two flash cans: one for indicators and one for hazards. I think you will need a second flasher can.

No. The Green Direction indicators will not flash when the Hazard Lights are energized.

The power to the turn signal circuit is comes from Fuse #7 (which is only energized when the ignition is ON). However, the power for the turn signal flasher unit is routed via the Hazard Switch OFF switch position, so it only energizes the turn signals when the Hazard switch is OFF. If you don’t have the wiring to the Hazard switch correct, you will not get power to the turn signals. The appropriate wires are the two Green wires shown as dotted lines on the Jaguar Wiring Diagram - dotted because they only exist when the Hazard Light (which was a US only fitment) is in place.

If you have the correct flasher unit, it should work with only one lamp per side, but the flash rate may not be correct. In a worst case, the one light may come on, but not go out - ie no flashing.

I have 2. Replaced the hazard one after I fried it by testing it wrong. Original Lucas. Hazard flashers now working.

NOW, I need turn signals (directionals)

Have the flasher on the A post also Lucas, dated 11/65. it tested as working on the bench. but I don’t get any action out of the turn signals.

I have the fuses out to prevent melt down. I used a power probe three to supply 12 volts to both sides of fuse #7, Hazard switch off, ignition on and I got nothing. If everything is right I should have gotten some flashing with one directional each side? Am I correct in thinking that?


Ok Bill
Is there power going to the directional switch…. From LGN from the flasher can to the switch ?
Do not use the purple/ brown wire that also goes to the switch and Carrie’s 12v that is for the high beam flash

Is there power from the GR and GW when you switch the direction indicator

Let’s see how you go with that

Yes, assuming that the turn signal switch is in place, and you move the stalk in the appropriate direction.

Your Hazard Switch should have two Green wires connected to it - one with a black band around the end. One of these two wires should have power on it when Fuse#7 is powered by the Ignition being ON. If neither wire has power in these circumstances, then that is your problem. If, on the other hand, one of them has power on it, it should be connected to one of the pair of terminals on the Hazard switch which have continuity between them when the Hazard Switch is OFF. The other Green wire goes to the other terminal of the pair. That wire should then route the power to the B terminal of your turn signal flasher unit.

Are you saying I can’t do that by only powering up #7, is the ignition switch on a separate circuit?

If you power up fuse#7, that’s all you need to do. All I meant was that in normal circumstances, fuse #7 is powered up by turning on the ignition.

thanks, will try tomorrow. Today has been a tough day in and out of the garage.

another tough day repairing mess house workmen made.

Got a few to do this:

Hot wire to fuse #7. Hazard switch off. Directional stalk activated to left. Check back of hazard switch. Both Green and Green with black band have power. If I understand the numbering this is postion 5 and 6 on back of hazard switch. No directionals moving. Check flasher can: B and L both have power. After about maybe 2 min elapsed I feel the flasher can and it is hot to the touch. Not hot enough to burn you but, more than just warm.

So what does that tell us?


B and L on the direction indicator flasher having power is good. The fact that the can gets warm after a while implies that there must be some current flowing too. There should be a Green/Brown wire on the L terminal of the flasher which should go to the turn signal switch. It would be worth checking that you have power there too. If you do, then it’s down to the turn signal switch or the way that it is wired.

I have power at the grn/brown wire at the flasher, I have power at that tab that leads into the flasher but at the other end where two grn/brown join the directional signal grn/brown I have no power.
With directional switch on, I get flashing power at the L terminal.

I don’t want to believe that what must be 6 in. of grn/brown that travels through the harness to directional switch is dead!!! I checked that entire harness for continuity before I put it in.

Can you come up with a different reason?

Pulling that harness out intertwined with all the rest may result in suicidal depression.

I’d like to clarify this, as your description leads me to believe that something may be awry, or I’m misunderstanding what you are saying:

The Green/Brown wire at the flasher unit (under the dash on the LH side) should be connected to the L terminal of the flasher unit. If that wire has “flashing power” when the turn signal is on, then it must be presenting a load to the flasher unit, which causes it to turn on and off. That’s what one expect if the turn signal light)s) were connected, but as I understand it they are not flashing.

That Green/Brown wire at the flasher unit should connect to one of the wires on the short loom at the turn signal switch. The Jaguar Wiring Diagram says that short wire should also be Green/Brown, but I recall seeing that some replacement turn signal switches use different color wires, so I wouldn’t assume that. I’m puzzled that you talk about “two grn/brown” wires joining the direct signal grn/brown, as I think that there should only be one. Unfortunately, I don’t have a 4.2 S1 LHD to compare with to be sure. I can’t help feeling that I’m not understanding your description. Maybe a couple of photos would shed some light?

I have only a RHD so maybe different in LHD ……but I recall that there is a joiner in that area also for the reverse wire that comes off the gearbox …it is DGN but on my wiring loom was LGN …… I’m wondering if there is a possibility of a cross wiring …


You may have got it! The Jaguar Wiring Diagram shows a 3-way connection of three G/N wires for the reverse lamp. If that is located in the same area, maybe Bill’s car has got them mixed up. Maybe worth looking to see if the Reversing Lamp is flashing… :grinning:

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I don’t even see a reverse lamp on my wiring diagram.

edit: no , i see it now.

The reverse lamp does light when I put 12 v to the switch on top of trans with lever in reverse slot

Does it also flash when you put the turn indicator switch in either turn position with fuse #7 powered? It’s a long shot, but from your observations there must be some load on the Green/Brown wire from the flasher unit, or it wouldn’t be pulsing on and off. Maybe repeat the test in the dark and see if any lamp is flashing…

Could there be a problem with the connector at the 3 G/N wires under the dash? Pull those apart and check for continuity along the wire from the flasher to that point.

John North
S1 4.2 Roadster