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MG TD TF 1500 - TD signal flashers

I was just reviewing the archives about flashers for '52 TD's. Seems quite a few people have run into a problem I solved a few years ago. The problem is that the dash indicator light is ON when the lights on the front wing are OFF, and vice versa. Some previous articles have recommended that a Wagner 550 will work, it won't. I have a feeling that Wagner put out a batch of 550's that were really 537's, which are listed as alternating. Finally tried a 564, this has the panel light wired correctly for our 'T' series!

Now it does not have a right angle bracket as does the Lucas. So uncrimp the Lucas and ditto the 564, it then will fit right into the Lucas housing. Then if you want use a sealed beam headlight socket to make the electrical connmections to the flasher unit. Much neater than the original nuts and bolts connections.

The date in my notebook says 6-20-00, been working fine ever since.
Good luck,
R. K. (Bob) Jeffers

Bob, if you look at the TD's wiring diagram you'll see that the original design is such that the indicator lamp is, indeed, out of phase with the side lamps. It's not easy to find flashers that work properly without paying the rediculous prices of vendor you-know-who.
Bud Krueger

If you have a PepBoys in the area, the heavy duty thermal flasher they stock in the electical aisle works fine. It sells for about $5. I use this with my halogen tail lamps.

It does not have the mounting bracket.

Evan Ford - TD 27621

Evan - The heavy duty flasher units are not a good choice to use for turn signals. They are designed to operate at the same flashing rate regardless of the current through them, so they will continue to flash as normal even when one of more bulbs are burned out or if there is a short at any of the sockets. Standard flashers are designed to flash at the normal rate for a given amount of current through them (current equal to two bulbs in parallel). If the current is above that level (as when a short occures) or less than that level (as when a bulb is burned out) it will flash faster or slower than normal or not at all. They are designed this way as a safety feature, since a change in the flashing rate (or no flashing) will aleart the driver to the fact that something is wrong (kind of like the check engine light on modern cars. And speaking of modern cars, their turn signal flashers operate the same way). The heavy duty flasher units were meant for temporary use when trailer lights are added to the turn signal circuit or for when the signal lights at all four corners of the vehihicle are in use as hazard flashers. Cheers - Dave
David DuBois


I use the heavy duty flasher with the 35watt halogens in the rear and standard bulbs in the front. I also have added a 4-way (hazard) switch just in case. The flasher seems to work well for each of these uses. As far as the bulb failure goes, I have a great way to check this. With 35watt rears, the ammeter jumps every time the rear bulb flashes on. (Same for checking brake lights - 70watts plus the third brake light.)

Safety Fast,
Evan Ford - TD 27621

Evan - In your case, with that amount of power at the rear, there is not much choice other than to go with the heavy duty flasher, the standard flasher would be flashing so fast that the light would look like they were not lighting up at all. As long as you have a way to tell when a bulb is burned out, then you are in business. Cheers - Dave
David DuBois

To All, --- Bud K. and I have exchanged several emails off the board. The conclusion is that the dash indicator and the wing lights are in-phase with a standard Lucas type flasher. But may well be out-of-phase with other type flashers. The Wagner 564 gives identicle results to the Lucas.
Regards To All,

R. K. (Bob) Jeffers

This thread was discussed between 31/05/2005 and 02/06/2005

MG TD TF 1500 index

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