Signal flasher on trailer wiring

Submitted: Monday, Jun 27, 2005 at 12:16
ThreadID: 24222 Views:1878 Replies:5 FollowUps:12
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Hi all. The wiring plug for the trailer is not getting any signal for indicators at all. Traced it back on the weekend and found (what I later discovered) to be two flashers, one on each left/right wire. As I understand it, the signal flashers should be under the dash and I can certainly hear them, so why would there be two other flashes downstream from there in the trailer wiring? Isn't the flasher meant to have contstant voltage in, rather than intermittent? I was thinking perhaps that is why its not working, it does click, intermittent signal goes in and doesn't come out. I was going to just bypass the flasher but wasn't sure why they were there... I bought the truck 2nd hand, and the trailer signals have never worked. If it matters, its a 90 series.
Tonester
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Reply By: tessa_51 - Monday, Jun 27, 2005 at 12:34

Monday, Jun 27, 2005 at 12:34
Cant help with the wiring technicalities, but if you are using a flat seven plug/socket the round split terminals on the plug (trailer end) can close up from having been constantly worked sideways to extract from the socket. Try opening them up slightly with a stanley knife and see how you go.
hope this helps

Tessa
AnswerID: 117677

Follow Up By: Max - Sydney - Monday, Jun 27, 2005 at 17:22

Monday, Jun 27, 2005 at 17:22
Tonester

Make sure you really open out the pins like Tessa says. I spent hours on my caravan a few months back - tracking wires, trying to fathom the mysteries of Toymotor wiring and tracing caravan wiring, even bought a new car plug to fit. It was the two flashers (end pins) and the stop light (next to bottom).

In desperation, I opened up the pins on the plug with a stanley knife and Hey Presto! - the problems disappeared. Its a real weakness in the flat plug design. Over the years I had it on the round plugs too.

And failing that, make sure the wiring is to standard on the trailer.

Max
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Follow Up By: Tonester - Tuesday, Jun 28, 2005 at 08:53

Tuesday, Jun 28, 2005 at 08:53
Thanks guys. Will check that as soon as I can get current as far as the pin plug itself! ha! But following on, a thought is to do the same to the flasher, perhaps.. maybe. Tonester.
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FollowupID: 373143

Reply By: ColinD - Monday, Jun 27, 2005 at 12:47

Monday, Jun 27, 2005 at 12:47
Tonester, if the indicators on your vehicle are working, then the flasher units are not the problem. Commonly scotch locks are the fault, you will find these at the point that the trailer wiring connects to the vehicle. Find this point and check the power there.
Have fun................col
(solder and insulate the connections)
AnswerID: 117685

Reply By: Tonester - Monday, Jun 27, 2005 at 13:00

Monday, Jun 27, 2005 at 13:00
The truck and all its lights are fine, no issues with connectors, or sockets etc.

It pertains only to the wiring going to the trailer wiring plug. An indicator wire has signal as it goes into its flasher, and none coming out. My question is along what these *downstream* flashers are meant to do, when there is already a flasher under the dash.

Tonester
AnswerID: 117692

Follow Up By: ColinD - Monday, Jun 27, 2005 at 13:36

Monday, Jun 27, 2005 at 13:36
Not familiar with Toyota, but some vehicles have load sensing units. These sense the extra current draw used by the globes on the trailer, and add to this so that the flash rate remains the same.
Hope this helps..............col
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FollowupID: 373004

Follow Up By: Tonester - Monday, Jun 27, 2005 at 13:52

Monday, Jun 27, 2005 at 13:52
Hey Col. Could be... current, transistors, capacitors, ummm. I tried to find info on thse things, and understand it, but electronics wasn't my forte. All I remember from school is watts=voltages*current!
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FollowupID: 373009

Follow Up By: BenSpoon - Monday, Jun 27, 2005 at 20:15

Monday, Jun 27, 2005 at 20:15
sounds odd- perhaps there were fuse dramas with the factory setup running extra lights.
Check for a second relay closer to the battery. Is there a steady current on the trailer pins when the car's indicators are on? Keep in mind it should be pulsing on and off at the pin. If it is a constant voltage, that could be a flasher can for left and one for right. Can you run 12V straight to one of the flasher cans on the trailer and see the result?
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FollowupID: 373089

Follow Up By: Tonester - Tuesday, Jun 28, 2005 at 08:49

Tuesday, Jun 28, 2005 at 08:49
Hi BenSpoon. Yeah, the pins get current intermittently, like an indicator flash. Good idea on running 12v straight to the flasher. I might even just swap the trailer one and main indicator ones around and see if the truck lights still work. Maybe it is just a bung flasher can.

I spoke to an auto elec yesterday, the only thing they offered (without taking it in there of course) was to check the fuse box. Neither the auto elect or Toyota could say whether two flashes will work in series or not. Both say the current draw thing might be why, but need to take it in. Was kinda hoping some smart bugger on the forum knew the answer!
Tonester
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FollowupID: 373142

Follow Up By: BenSpoon - Tuesday, Jun 28, 2005 at 21:26

Tuesday, Jun 28, 2005 at 21:26
can you get any markings off the cans? Are you certain they are flashers? They may be ballast for an internal fluoro or something wierd- Got anything that saps high current on the trailer, like a firdge compressor? I have looked into one farad caps before for my amp (they act as electrical ballast to provide steady volts) I could imagine the volt drop over standard gauge wire playing with a fridges low voltage cutout.

Have you checked the trailers plug for shorts between pins? I couldnt imagine a second flasher can downstream being too successful having its power cut off when it tries to close the circuit.
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FollowupID: 373218

Follow Up By: Tonester - Wednesday, Jun 29, 2005 at 08:46

Wednesday, Jun 29, 2005 at 08:46
The thing is a Siemens 12V. I took one into to Repco and they also said they were flashers. It certainly clicks merrily. The trailer itself is a normal, beatup, 30 year old thing, had it connected to many other cars fine. Yes, also broken apart all the wires & plugs I could see, including the all the conduit. All ok as far as I see. Still, I have two things to try - check the fuses, and run the 12V direct. Going to have to wait till weekend though. Failing that, Toyota here I come (they might check it for free...goodwill and all!).
Tonester
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FollowupID: 373244

Follow Up By: BenSpoon - Wednesday, Jun 29, 2005 at 10:00

Wednesday, Jun 29, 2005 at 10:00
Haha
"they might check it for free" lol
Good one mate.
Keep em coming.
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FollowupID: 373246

Follow Up By: Tonester - Wednesday, Jun 29, 2005 at 10:47

Wednesday, Jun 29, 2005 at 10:47
yeah, hehe... fair cop that! I did say "check", not "fix" though!
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FollowupID: 373252

Reply By: tonysmc - Monday, Jun 27, 2005 at 15:22

Monday, Jun 27, 2005 at 15:22
Have a look at if it is wired up as a 7 pin or 5 pin. Believe it or not they are not the same. The indicator sockets are moved one pin around. brake, earth and tail lights remain the same. This is australian standards and whoever thought up this idea should be shot. Tony
AnswerID: 117725

Reply By: drivesafe - Wednesday, Jun 29, 2005 at 09:03

Wednesday, Jun 29, 2005 at 09:03
Hi Tonester, are the stop and parking/clearance lights working.

If not then the problem might be a faulty earth connection.

Cheers and best of luck, trailer wiring problems can be a most frustrating find and fix.
AnswerID: 118006

Follow Up By: Tonester - Wednesday, Jun 29, 2005 at 09:12

Wednesday, Jun 29, 2005 at 09:12
Hi drivesafe. Nah, all fine bar the indicators.
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FollowupID: 373245

Follow Up By: drivesafe - Wednesday, Jun 29, 2005 at 10:14

Wednesday, Jun 29, 2005 at 10:14
Then you sure have an interesting problem, again best of luck and don't forget to let us all know how you get on.
Cheers
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FollowupID: 373247

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