indicator flasher problem any ideas?

[roy mawbey]

Guys,

I put this on DDK today. It explains my problem but I did take some photos as well if my text is not clear.

I think the main question is do you think a flasher unit if it fails could or should blow a fuse which it has in my case.

This is the text I wrote on DDK

http://www.ddk-online.com/phpBB2/viewtopic.php?f=3&t=50149

Cheers friends

Roy

[Phil Planck]

Roy
Good luck with this problem. I don't have an A wiring diagram. If the T6B flasher system is the same I can look at that. I would track the wire from the fuse to the flasher unit and look for all hot paths. One of those has grounded out somehow. At least you have a fuse to protect the wires from burning up. If you have an ohmmeter you could leave that fuse out and attach one wire to a good ground and start probing the various wires to hopefully find out which on is grounded.
Phil

[roy mawbey]

Thanks Phil,

I have studied the drawing more now and notice Fuse 1 protects also the brake light switch. The three wires coming out of the flasher reception have tails with bullet ends. If its possible I will check continuity of each as well as the wiring to each indicator on the car and the stop light switch.

I would like to think its an internal short inside the flasher unit but don't want to waste my last original spare one just plugging that in. I will try with a fuse place but no flasher in the socket ( and the indicator stalk in neutral ) the brake lights just to see if they work.

I do know the fuse popped directly I moved the indicator stalk yesterday juist have this feeling its the flasher unit. Has anyone had a number 1 fuse blow and just replaced the flasher?

I will do the checking as you mention.

This drawing was passed on to me today for a T2. might be useful

http://www.cyberwerkstatt.com/Members_Only/T2_Pgs/T2_BrakesTurnSignals_Final.htm


Roy

[Phil Planck]

Roy
Interesting diagram. Looks like with the key on you should be able to get brake lights working. If that does not blow the fuse, then that eliminates a lot of areas for potential grounding so you can concentrate on the blinker. How about putting an ohmmeter on the hot input terminal of the removed, original blinker and touch the can. Should be an open circuit.

[roy mawbey]

Phil,

I have sorted the problem The flasher reception was I think the problem. I checked with my AVO meter every bulb, every connection, made continuity checks through the circuits and finally put in my spare original flasher and double checked the continuity of the wires to the stalk and the fuse. ( That took a long time )
I had 3 spare fuses so took a chance as I could find no broken or chaffed wires and it works fine.

I have learned from the excercise though quite a bit. I have some photos which I will put on which show the flasher internals, as I took one apart.

Cheers for the help!!

Roy

[Phil Planck]

Glad you solved it Roy. Yes, electrical debugging can take time. Looking forward to your findings.
Phil

[roy mawbey]

Been a while but pleased to say the flasher works perfectly. I did take photos which you can see below. I have made comments for each one in case anyone else has the same problem. This concerns only a 356A T2 other models might vary.



The photo above shows the fuse board the r/hand end 8 amp fuse ( no 1) blew. This fuse also protects the brake light switch. I therefore replaced the blown fuse but.. did not move the indicator stalk but just tried with ignition on, the brake light it worked so took that was out of the equation.



The above photo shows the spare Hella flasher ( I bought from a breaker in 1971 ) the other one has been in the car for 45 years.


The above shows the internals of the failed flasher. Its complex and difficult to check. Nothing looks burned or broken, the continuity checks were the same for both this one and the spare. I had to de crimp the aluminium body to expose the internals.


The above shows the back of the reception for the flasher. Three wires and the central brass shaft with the hole for the location screw is peened over in manufacture. I could not remove the mica back plate to check the connections. It seems the factory would have ordered these in quantity all with correct colour coded wires. I see no way these were assembled by factory fitters. The 3 wires around 9 inches long had bullet ends which connected under the dash to the corresponding loom wires. I did a continuity check and all were okay to the loom. ( I had checked the wiring to each flasher beforehand )


The above shows the front of the flasher reception. I had removed the threaded screw from the reception and I changed it for a longer one. The screw goes through the bulkhead to under the front lid. It was covered in factory sealing and difficult to remove and replace.
You will notice the 3 entery sockets for the prongs of the flasher. One of the failed flasher prongs was bent somewhat. As its difficult to see the flasher in place I straightend the socket and inserted the spare flasher carefully before then fitting the complete assembly to the bulkhead and connecting to the loom.


The above shows an earth strap? Strange place but thats all I can think it is. The central location screw could be used but would rely only on the small diameter washer and nut.


Above shows the flasher in place and connected and all working fine.
I have a feeling either one of tbe flasher stalks either earthed inside the reception unit I could not open or, the main copper coil inside the flasher had shorted out but not burnt? The three wires one to the flasher stalk the next to the fuse and the last to the indicator bulb in the tachometer were all okay.

That ends my tale. Not conclusive but took a long time to resolve. Maybe a flasher that fails always knocks out a fuse???

Roy

[JTR70]

Pretty good detective Roy! I learned a little something about the flasher system. If I have problems with mine I know who to ask! Well done!
Justin