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Alternate Hazard Switch - DPST

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lokiufgator Mike S
Evington, virginia, USA   USA
As the title says looking to replace the Hazard switch in my '78 with something else. I'm making a switch panel with toggles that have LEDs in the tips so I'd like to stay consistent. Since I have two IC flasher modules (turn and hazard) already it should be easy enough with a double pole, single throw switch to make sure the 2 sides of the car stay isolated if I can figure out the pins on that back of the stock switch.
I can't figure out the Lucas wiring as it attaches to the stock switch to make the change over. Can someone describe what each of the pins on the socket are for?
I've wired my house from scratch and more cars than I can count but never tried reworking the hazard circuit before.

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lokiufgator Mike S
Evington, virginia, USA   USA
Might have answered my own question with more searching. Based on this thread and Dan D's post, I think a double pole, double throw switch might be the answer. Set the NC throw to supply power to the turn flasher and the NO throw to use power coming from the hazard flasher and out to each side and the dash indicator for the hazards?
Thoughts?

Two Bs Avatar
Two Bs Gold Member Kent McNeill
London, Ontario, Canada   CAN
I saved these pictures as I want to add Hazards to my 67BGT. They might help you.

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hazard switch change.jpg    42.2 KB
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Donthuis Avatar
Donthuis Don van Riet
Rijswijk, ZH, Netherlands   NLD
Both solutions work IMO, the first one only require a single flasher unit, not seperate ones for indicator and hazard usage.

In this first solution the flashing frequency will differ between indicator and hazard situations since the loads are different: only bulbs on one side of the car in indicator position, doublesided with hazard.
If you want the same frequency a single LED capable flasher unit is the best choice: their frequency does not depend on the load. 2 and 3 wire LED flashers exist (3d wire is for earth/mass connection)

The OP final choice will also depend on which hazard switch is easiest to find, double off/on (NO) for the first one is maybe easier to find than the double switchover (NO/NC combined) eye rolling smiley

PS With a MKI B the first solution with a simple switch and only a single LED capable/load independent flasher is tempting cool smiley

In reply to # 3661049 by Two Bs I saved these pictures as I want to add Hazards to my 67BGT. They might help you.



Edited 3 time(s). Last edit at 2018-01-13 10:55 AM by Donthuis.

JNorthrup Avatar
JNorthrup Jim N
Las Cruces, New Mexico, USA   USA
I like the idea of the second flasher directly wired to the hot 12vdc.
That way, if needed, you can leave the car without the key in the ignition.

Fairfield, CA, USA   USA
Tossing about DPST terminology and such confuses me.<G>

The switch I use has 3 rows of 3 contacts each. The center row is power in (3 contacts for power in...one could wire 3 different accessories using each column for a different one, switch would then work all 3). When the toggle is down, it connects the center row to the top row of contacts, energizing that circuit (for the "off" position on the hazards). Flip switch up, turn blinkers on, it connects center to the bottom row.

Use an ohm meter to verify and understand the way it installs and works.



1973 Pale Primrose Roadster. A nice 10-footer!
SUs, Datsun 5-speed

Donthuis Avatar
Donthuis Don van Riet
Rijswijk, ZH, Netherlands   NLD
Yes this was the main idea behind the original BL setup, which permits hazard flashing from an always hot battery line. I wonder whether car type approval required this from the beginning.
If so, it will also influence MoT/APK requirements! I do not have Website acces to our Dutch APK ones so can not check.

Let me rephrase my earlier advice to: using either of the three later solutions is safer and to be preferred as regards functioning without the ignition switch on, i.c. after an accident.
This requires either using the original hazard switch or an extra bypass hazard switch with doubled contacts for switching the left and right side bulbs over from one flasher circuit to another.

PS Post #6 mentions a switch with tripled contacts for switching over: this will enable Mac to switch again a bulb on too, when hazard flashing is on. This bulb circuit disappeared in the "later" setup

In reply to # 3661092 by JNorthrup I like the idea of the second flasher directly wired to the hot 12vdc.
That way, if needed, you can leave the car without the key in the ignition.

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