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MG TD TF 1500 - Turn Signals

My 52 mg td had the upgraded wiring harness when I bought it. The switch went bad and could not be repaired. I replaced it with an on-off-0n toggle switch which seems to work properly. I have taken the relay apart cleaned it etc. and operated it under load and it seems fine. I own 3 flasher units. Napa EL-13, Moss replacement, and Napa 550. The only one that works is the Napa 550, but the P terminal is always hot, causing my indicator light ( I installed it with a direct wire to the flasher's P terminal ) to always be on, but it does blink with the signal. The other two flashers ( expensive ones ) do not work. I would think that all I needed was a new 550 except the other two are new and suppose to work and do not. The Napa EL-13 does nothing, The Moss gives me a continuous light and no flashing signals. I have a light green wire,dark green wire,and green with brown stripped from the harness. The light and dark green are always hot at 12v. I can use either one to the X terminal with the same results. I wire it according to the N23 page with the green brown to #1 on the relay and have switched wires as much as I can with no positive results. any suggestions?
W E Miller

Are you running incandescents all around? The EL-13 should work with them just fine, if not sometimes 'horsing' around with the connectors will distrupt the internal orientation and cause the unit not to flash. Since it is transluscent, you should be able to see if everything is working or not.

The X terminal gets the green wire (switched and fused) from the car. The P terminal gets the light green wire which should not be hot. Find the other end of the light green wire and find out what it is cross connected with. It should go only to the panel light or buzzer. For our cars, the P terminal should only be hot when the flasher can is opperated by the relay, (i.e. the L terminal is hot via the green with brown wire passing current because the Turn Signal relay closes and the lights see a ground.

Sounds to me like the light green wire is going somewhere that is picking up power. If both the light green and green wires have power on them, of course either will power the flasher, but only the green one, connected to the X terminal should be doing that job.

The green with brown wire should connect the L termainal to the relay connection 1 which provides the power to the turnsignals. Once the relay provides the path to the lights and thus the ground and current can flow, the flasher can heats up and turns that power on and off while the relay holds the contacts on the correct side to flash.

Finally, the brake lights also go through the relay box, but only the light that is NOT flashing gets its power from the brake switch when the turn signals are flashing.

Hope this helps,
dave
Dave Braun

Maybe this will help too...

Basically the circuit is like this:
Green (Switched, Fused) wire goes to the turn signal flasher terminal X. The bimetalic switch in the flasher goes to the L terminal. The green with brown wire goes from the L terminal to power the relay box at terminal 1. It doesn't pass current until the relays activate and closes the switches on the lights, but if you checked the L terminal while the X terminal was provided Voltage, it would show voltage too if you used a test light or meter and provided a ground. If you provided enough of a load at the L terminal, say, two lamps, it would flash.

When the relay box is switched on from separate currents at either terminal 4 or 8 as needed, and current from 1 passes to the turn signal lights, the bimetalic switch heats up and turns off the power to the L terminal which turns off power to the lights. When the bimetalic strip cools, the power flashes back on. While the L terminal is seeing current, the P terminal sees voltage as well, and that is where the light green wire is connected which then provides current to the indicator lamp or buzzer.
Dave Braun

Thanks Dave. Yes all the bulbs are original and working. I have tried to trace the light green wire and it appears it is attached to the switched terminal on the switch/horn. More investigation this afternoon. Still does not explain why The P terminal stays hot and the other two flashers do not work except for the napa 550.
Your 2nd posting about testing has me thinking.

Thanks.
Bill
W E Miller

Bill,

If your MG is positive ground (earth) the NAPA EL-13 will likely not cause the turn signals to light (or flash). See my posting a couple of days ago about this very situation.

Larry
Larry Shoer

Bill
Interesting you mention your issue with the flasher light. My TF does this too. I had a non functioning dash blinker but working turn signals when I got the car. I did some work on the dash light and bought a Moss replacement flasher unit. My dash light is always on. Everythings works normally, so I have let it be.
Maybe as this discussion flows, I'll glean some new information and perhaps get it working properly.

Tom
'54 TF
Tom Norby

Ok, I traced the light green wire and it did go to the ignition switch. Why. I have no clue, however, who ever installed the new harness pig tailed a lot of the wires to the instrument panel. colors don't match at final destination. Just wanted you guys to know how much fun this is.
I switched the light green wire to the signal light. It works etc. I took the car for a drive and did not notice anything that was not working right. However the only flasher that works is the 550 and the flasher light is on all the time but does flash with the signals.
Anyone vacationing on Kauai, stop by and look at my 52TD and receive a free EL-13 flasher or Moss replacement. We live in Princeville on the North Shore. kauaibillm@gmail.com

Thanks to the guys who posted. Larry made me feel better and we are both waiting for the info about a flasher that will work with positive ground.There was one post a while back that suggested that an HD-13 or SD-13 would work. Does anybody know for sure. And thanks to Dave. About a year ago you guys helped me solve a starting problem. It took two weeks but we did it. Love this forum

Bill M
W E Miller

You're welcome Bill. As an aside, the EL-13 works fine on my pos ground car.
Dave Braun

Dave,

I wonder if the NAPA EL-13 was redesigned and now doesn't work on positive ground cars. The one I tried was purchased within the past month. How old is yours?

Larry
Larry Shoer

I bought my EL-13 less than a week ago. However, we are a small Island and they could have had it in stock for some time. Oh well, it doesn't work and I don't think it is my fault. I will just live with the signal light being on until someone comes up with a fix.
W E Miller

It's certainly possible, Larry. I purchased mine in July of 2008. NAPA still lists it as a 'Electro-Mechanical' flasher.

A solution is to provide a wire from each output terminal at the relay box, through a diode, to the panel light. The current will go through the panel light without going 'back' to the other side of the car. Then, you could use a common two pole flasher or the 550 flasher and the panel light would flash With the lights on the car, not out of synch.

warmly,
dave
Dave Braun

This thread was discussed between 07/10/2011 and 08/10/2011

MG TD TF 1500 index

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