codekiddie
Active Member
Having recently seen several topics on indicator or hazard problems, and in a bid to resolve my own problems with hazards, I thought I would post my cleanup procedure of the hazard warning switch, (even though this turned out not to be the culprit in the end 
)
First a picture of the complete switch. The RED square is the inner contact ring that either connects all of the outer GREEN indicator wired connections together, or all of the outer BLUE hazard wired connections together. The switch is currently shown in the hazard position which is why the RED inner connection is in line with the BLUE hazard connections.
I found the original circuit for my 1972 3500S unclear about the switch function, so I have added the original and a modified version. The RED line in my circuit is the inner connection of the hazard switch. When in the indicator position, the inner connection joins the indicator relay (87) to the indicator stalk (114). When in the hazard position, the inner connection, joins all four, (hazard relay (68), hazard repeater bulb (integral to switch), and left and right indicators (111/112 - 116/117) / and dash repeater bulbs (113/115)).
To remove the wired connections, place a suitably sized flat bladed screwdriver as shown to release the locking tab.
The connections may then be removed from the switch body.
The switch body with all outer contacts removed.
Make a note of where this tab is located for re-assembly purposes. It ensures that the repeater bulb outer connection will connect to a hazard warning connector.
Remove the locking ring from the switch shaft....
....allowing the centre portion to be removed from the body.
A picture of a connection partially cleaned showing the difference.
A fully cleaned contact ready for re-assembly
Be careful with this contact on the inner part, it is the outer connection of the repeater bulb and is easily bent. It connects to one of the hazard warning connections of the switch.
The switch cleaner I use on the contacts after cleaning them up.
After cleaning all of the wired connections, (and the inner ring connection), re-assemble the switch. As the HBOL likes to tell us, re-assembly is the reversal of dis-assembly :shock: :shock: :shock:
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In my case the fault I had was that the hazard lights would initially work, then stop after a few seconds, then start again for a while etc....
The fault was eventually traced to the infamous fuse-box, whereby the fuse that services the hazards relied upon another fuse for continuity of power. Whilst looking at the fuse-box whilst the hazards were on, I noticed a faint arcing due to the dirty contacts of the fuse-box. A quick cleanup of the fuse-box contacts saw the end to that problem.
This fuse-box problem is quite well documented on the site, with some scary pictures of melted boxes, due to the heat buildup around the dirty arcing contacts :shock: :shock: :shock: It is on my to-do list to come up with a fix for this design flaw.
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The original indicators / hazards design uses two different relays, each capable of serving a specific number of bulbs. The hazard relay needs to be able to cope with twice the number of bulbs as a standard indicator relay. The relays work on a bi-metallic strip design, whereby the current drawn heats up the strip to the point where the contacts are broken. When the strip cools down sufficiently, the contacts are connected once again and the process repeats.
Why not simply use the higher rated relay for both? The answer is that the relays on/off times rely on how quickly the strip heats up, allowing the contacts to break. If we used a hazard relay for indicators, then only half the normal current would be drawn and therefore the strip would take longer to heat up to the point of the contact breaking. The result would be slow flashing indicators.
In the same way, if an indicator bulb blows, then less current will be drawn than normal, (around 50% of normal), so you may find the indicators either stay on permanently or flash at a very slow rate compared to normal. With the hazards if a single bulb blows then the current draw would be roughly 75% of normal so you could get a similar result.
I believe the modern relays do not rely on the current draw to determine flash rates, and indeed I have seen several circuit diagrams for moderns that use the same physical relay for both indicators and hazards.
Bad earths can cause a multiple of results ranging from the same results as a blown bulb, to sidelights also flashing etc...
Hope this helps in some way to anybody with such issues
)First a picture of the complete switch. The RED square is the inner contact ring that either connects all of the outer GREEN indicator wired connections together, or all of the outer BLUE hazard wired connections together. The switch is currently shown in the hazard position which is why the RED inner connection is in line with the BLUE hazard connections.
I found the original circuit for my 1972 3500S unclear about the switch function, so I have added the original and a modified version. The RED line in my circuit is the inner connection of the hazard switch. When in the indicator position, the inner connection joins the indicator relay (87) to the indicator stalk (114). When in the hazard position, the inner connection, joins all four, (hazard relay (68), hazard repeater bulb (integral to switch), and left and right indicators (111/112 - 116/117) / and dash repeater bulbs (113/115)).
To remove the wired connections, place a suitably sized flat bladed screwdriver as shown to release the locking tab.
The connections may then be removed from the switch body.
The switch body with all outer contacts removed.
Make a note of where this tab is located for re-assembly purposes. It ensures that the repeater bulb outer connection will connect to a hazard warning connector.
Remove the locking ring from the switch shaft....
....allowing the centre portion to be removed from the body.
A picture of a connection partially cleaned showing the difference.
A fully cleaned contact ready for re-assembly
Be careful with this contact on the inner part, it is the outer connection of the repeater bulb and is easily bent. It connects to one of the hazard warning connections of the switch.
The switch cleaner I use on the contacts after cleaning them up.
After cleaning all of the wired connections, (and the inner ring connection), re-assemble the switch. As the HBOL likes to tell us, re-assembly is the reversal of dis-assembly :shock: :shock: :shock:
----------------------------------------------------------------------------------------------------------
In my case the fault I had was that the hazard lights would initially work, then stop after a few seconds, then start again for a while etc....
The fault was eventually traced to the infamous fuse-box, whereby the fuse that services the hazards relied upon another fuse for continuity of power. Whilst looking at the fuse-box whilst the hazards were on, I noticed a faint arcing due to the dirty contacts of the fuse-box. A quick cleanup of the fuse-box contacts saw the end to that problem.
This fuse-box problem is quite well documented on the site, with some scary pictures of melted boxes, due to the heat buildup around the dirty arcing contacts :shock: :shock: :shock: It is on my to-do list to come up with a fix for this design flaw.
----------------------------------------------------------------------------------------------------------
The original indicators / hazards design uses two different relays, each capable of serving a specific number of bulbs. The hazard relay needs to be able to cope with twice the number of bulbs as a standard indicator relay. The relays work on a bi-metallic strip design, whereby the current drawn heats up the strip to the point where the contacts are broken. When the strip cools down sufficiently, the contacts are connected once again and the process repeats.
Why not simply use the higher rated relay for both? The answer is that the relays on/off times rely on how quickly the strip heats up, allowing the contacts to break. If we used a hazard relay for indicators, then only half the normal current would be drawn and therefore the strip would take longer to heat up to the point of the contact breaking. The result would be slow flashing indicators.
In the same way, if an indicator bulb blows, then less current will be drawn than normal, (around 50% of normal), so you may find the indicators either stay on permanently or flash at a very slow rate compared to normal. With the hazards if a single bulb blows then the current draw would be roughly 75% of normal so you could get a similar result.
I believe the modern relays do not rely on the current draw to determine flash rates, and indeed I have seen several circuit diagrams for moderns that use the same physical relay for both indicators and hazards.
Bad earths can cause a multiple of results ranging from the same results as a blown bulb, to sidelights also flashing etc...
Hope this helps in some way to anybody with such issues
