corolla 2000 turn signal to trailer

Makes more sense, howie II. Over here majority of trailers have the stop (brake) & signal lights combined. Very frustrating when it comes to needing some converter that doesn't work. The converter I've been used (tried two of them with same problem) are the Curt 56175.

mechanicalhobby wrote: ... needing to turn off the stop light while the hazards or flasher is active. That sounds quite annoying to always have to remember that, especially on a road trip.

It's not annoying at all. It is completely automated. And that's how it has to be. It is looked after by the switching circuitry that combines the flasher filament with the brake filament. I'm assuming you have not tested each individual trailer lights with 12V as I suggested, and then in combinations with 12V - ie, brake & left flasher, brake & right flasher? It wouldn't surprise me if it is a trailer fault - no or faulty ground for the brake/flasher bulbs. Yeah - front flashers are a different circuit. It is rare that I see stops lights operating on the front of a vehicle (ground faults excepted).    Older local and Jap vehicles had dual-filament flasher/parkers, but these days they are dedicated flashers with separate parkers, hence better contrast when flashing with parkers on. Most modern wiring uses dedicated lights for a function - ie, stop and indicators are separate as are parkers, indicators, and reversing lights.   USA is an exception. The 1:1 mapping makes additions, extensions & trailers etc a breeze. And forget LEDs etc. Even a properly working bulb system may not work with LEDs (LEDs are easily grounded thru other bulbs or parasitic voltages and grounds). Find out what is causing the problem first - ie, test the trailer filaments.

I did test the trailer on another vehicle, and that worked perfectly along with another trailer, but testing both trailers on the Corolla failed the test. I'll try your recommendation with testing each bulb & filament with 12v. Thing that get's to me is the wire converter installed in the back trunk. Sometimes the voltage comes out, and sometimes it has nothing coming out whatsoever. At least most of the time it fails. So I'll do the individual light bulb & filament test with 12v then if that looks okay, then maybe move the ground wire that goes into the converter and actually tap into the car's body instead of put it on a grounded nut. Got a feeling that maybe there is too many amps being pulled than what the system can handle, thus the converter shuts off. But first the 12v test and take it from there. Have to work today, but will test later on and will post the results.

Alright, so I did the 12v test, straight from the battery! Each light is working fine! But here is the interesting part, plugging the wire converter straight to the battery, ground to negative and each other wire individually connected to the positive, all worked as hoped! I then did an Amp test for each two sets of lights. And the results are around: Tail-light: 1.7 amps Stop-light: 3.54 amps Left-Indicator: 1.78 amps Right-Indicator: 1.78 amps Indicators-Combined: 3.54 amps (tested with both wires connected at same time) With trail light & stop light or indicators combined, I read a total of around 5.1 amps. The indicator/signal lights seem a bit high on the amps. The converter reads: "Maximum lighting load capacity Left/Right signal circuits (each) = 3.0 amps Trail/running light circuit = 7.5 amps": Not sure if that's the limit including the vehicle or not. But it seems there is a fair bit of amps being pulled. The car's fuse limit itself is 7.5 amps for the indicators. With the current 6 amps about being pulled for the car's signals or hazards combined, plus another 3.5 amps for the trailer, that's about 9.5 amps total. I think the converter may not be able to handle the amps being pulled for this particular vehicle, though the Curt company said it should work. I know the wire converter has some safety features that cuts out if there is an overload or short. Thinking if too many amps are being pulled, than the wires would heat up causing the wire converter to short out. Wondering if it's possible to get another type of unit that has it's own dedicated power source with it's own fuse. Would this be a good idea? Might go to the store and pickup something before it closes.

In summary, I think your problem is a bad ground to the converter. I think your suggestion to ground it locally to a body/chassis nut is spot on. That's about it, but I'll elaborate on other issues below... And that's great testing by the way - if only others were so capable! {**) My only additional check would be to power both indicators and stops at the same time and see if that load is ~3.5A or ~7A AND confirm that they are at full brightness. That will confirm whether single or dual filament stop/flashers, and eliminate bulb GND problems. Others issues etc (ie, oldfart's ramble:) I wonder where the converter is being grounded from. If it's from a single rear light GND which is only for one or a few bulbs (1.7A or 3.4A etc) else a relatively long and thin wire, then it will have a BIG voltage drop. You could measure the voltage between the converter's input or output GND and the body/chassis. If it's more than a few volts... The Amp readings seem fine, and the unit's "Left/Right signal circuits (each) = 3.0 amps" means 6A total. Yours are ~1.8A each. 1.7A x 12V = 20.4W so it looks like you are using normal 21W or 23W bulbs for stop and flashers. (P=VI) Tails total the same so I presume 2x10W or 2x7W plus some 3W for license plate etc - not that that matters. As to a converter with its own power source - no - the battery is its power source. And these units should work fine. As their blurb says, problems are usually in the grounding though I assumed they meant the typical grounding problems in trailers etc (especially those that think a ground is adequately supplied through the hitching device!). The only other problems should be in inadequate cable sizing. Or if the loads (bulbs) exceed the converter's rating, but you are well within that. And keep in mind that the only current relevant to the converter is the current going thru it to the trailer lights. It doesn't matter if the rest of the vehicle uses 100A for its tail (clearance/parking) or indicator etc lamps - that does NOT go thru the trailer plug.     [ **And to use a DMM's high current mode - without blowing it apart! Some insist on testing across batteries and BANG! (An ammeter is like a short circuit (ie, low impedance). A voltmeter is like an open circuit (ie, high impedance). Even 10A testing a 1.5V AAA battery will blow the DMMs fuse. And I dislike inserting the DMM probes in series with the circuit under test - I only have 2 hands! ]

Thanks. Good News! Got it to finally work! And it works perfectly! I did end up checking the ground to the converter by running a wire from the converter's ground straight to the negative terminal on the Corolla's battery. The result was the same problem! Here's what I did: I ended up ditching the current convertor which was the Curt Wire Converter 56175. To be honest, it was useless! Would have thought it would should have worked, but it just kept cutting out. I just don't think it is compatible for the Corolla, at least for my generation. I feel the Corolla just doesn't give it enough juice, so the converter cuts out. The Curt tech line said it should work for my vehicle. But tried two different Curt 56175 Wire Converters, and both failed on the Corolla. So went to an auto store and picked up another Wire Converter with one major difference! It had a 12v positive 20amp fused red wire on it that hooks straight to the battery. (What I had refereed to as it's own power source). The wire was a bit of a pain to guide it through the car from the front to the back, but managed to do it. My understanding is this converter get's signals from the same wires I had previously tapped into, rather than leech from the actual power from the car's lights. So when each light is turned on/used on the car, then the converter provides the power that is needed straight from the battery. The converter say's it's a Hopkins Short-Proof Power Taillight Converter. Part# 36365 The lights on the trailer are also much brighter than they were through the Curt converter/s. The converter I bought today is supposed to support up to 8amps per function. Not bad. It has the plug for 4-way, but it also apparently can be used for 5-way, 6-way or 7-way adapters, if I convert it to that that is. But 4-way I'm happy with. It wasn't cheap, spent around $80 for it, but very worth it. I spent too much time on it already and gave up on the Curt Converter. Could have got it cheaper online probably, but I don't have time waiting for this in the mail, as winter is coming fast. Do you have an idea what may have caused the Curt 56175 converters to fail like they did? I was thinking maybe the car can't keep up with the demand from the trailers, thus overloading the car causing the Curt converters to shut off power. Anyway, very happy that it is finally working! Thanks so much for your help with it. I learned a lot along the way.

I don't now enough about those converters to comment, though it sounds like the newie with the direct battery source uses the lamp feeds to switch relays (or MOSFETs etc) that connect battery power direct to the trailer. It may be that the Curt uses diodes or other circuitry, though I haven't bothered figuring out the conversion required. (I've done it so many times using various methods that I now have an aversion to even thinking about it, though I can recite the connections for the equivalent shared flasher/reverse filament switching using 2 DPDT relays etc.) Maybe one day my curiosity will cause me to investigate further. But I'm glad you got it working, though I'm disappointed it took another product and expen$e to do it. (And I hate unexplained but working outcomes - except for intermittent problems!) And I'm very glad you learned a lot. Things like this can be tricky as heck, but can still be broken down into simple steps - or rather, certain things eliminated (in this case the product LOL!). Best wishes. And as I alluded above, you have shown a great deal of competence. [Hey man, if "they" said it should (both!) work - but another product did - then I reckon it is not a simple problem. IMO - well done mechhobby; you might have to change your name to 'lechobby.]