Printer Friendly Forum Posts - 4-pin electronic relay for LED

Hi guys,
I'm new to the forum but not new to cars. I am an American living in a former Soviet country and I have a 1998 Vaz Niva. I am replacing the turn signal bulbs with LED bulbs and as such I will need to find an electronic relay. I would prefer not going the route of load resistors because it eliminates half the reason for the LEDs and that being reduced load on the system.

The Niva has a 4-pin relay that controls both the hazard blinking and the turn signal blinking (see #8 in the diagram below). Here is my understanding of the pinout below. What I need is an electronic relay that will give me the same functionality with my LED bulbs without blinking fast.

Pin     Color Description
1     Brown (+12v) 4 on Hazard switch
2     Blue/Red     (+12v) 7 on Hazard switch and 4 on direction indicator switch
3     Blue/White     5 on direction indicator light on instrument cluster
4     Black Ground

Note: the instrument cluster light is one light that blinks regardless of which direction the turn signal lever is pulled.

posted_image

An EP29 is a 4 prong flasher that can be used for LED's.

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My ex once told me I have a perfect face for radio.

Yeah, I was looking at the EP29. The wiring diagram shows that it can be used as a flasher relay or a hazard relay but does not appear to be usable as both like the stock relay is. Am I seeing that correctly? If not how would I wire it so that it mimics the stock functionality?

I was looking at the relay off european models of honda CBR and other models because it appears they are 4 pin instead of the 2 pin of their US versions and i was reading that its because the euro versions have hazard lights and the US ones dont. I cant find a wiring diagram of the relay to confirm though.

No 9, not 8 is the relay if that helps.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

I'm confused. Yes, 8 (in the diagram) is the relay. That relay however has an input from the hazard switch (9) AND from the turn signal selector switch (10) which, if I understand the wiring diagram of the EP29 relay, I can give it either or, but not both.

Sorry you're quite correct.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Try the EF26 which is a Combination TS & Hazard.

Is the EF26 the same as the EP26? I cant seem to find an EF26 for LEDs or a wiring diagram. I do see that both EF and EP models are combo hazard and turn flasher relay but i need to make sure the pinout is the same as the stock. It takes 3-4weeks to get thinks here and id hate to waste time and money on a flasher that doesnt work if I can find out before by looking at the flasher schematic.

OK, I got tired of not having some hands-on knowledge of what was going on so I got the multi-meter out and did some testing. Here is what I found:

Pin     Color Description
1     Brown (+12v) ignition
2     Blue/Red     (+12v) pulse 7 to Hazard switch and 4 on direction indicator switch
3     Blue/White     (+12v) pulse to direction indicator light on instrument cluster
4     Black Ground

OK, so my question is this. Pins 2 and 3 seem redundant. Since I'm replacing my dash bulbs as well with LED's couldn't I just get a 3-pin relay like the CF13JL-02 and wire pins 2 and 3 to the load pin? The total load on the relay will be minimal since everything is LED, so there shouldn't be any worry about overloading. Or am I missing something and need a 4 pin with 2 load pins like I have now.

@geepherder recommended the EP29 which is a 4 prong relay and I didn't think it would work but part of it is that I don't completely understand the pinout.

EP29 details

Does the "sense" output also pulse a 12v+ when the relay is activated? I can't get an explanation about it, so I thought I'd ask here. If so it's exactly the same thing as what I have.

EF29L LED Compatible diagram

EF29L Product page

Which Replaces
Napa EP29L

Thanks for the schema. Unless I am reading it wrong, sense wouldn't work for the second load, so I'm better off going with a three prong relay if I go that route.

Another route that I've noticed people are taking is "cutting" the track to the IC on the relay which senses a burned out bulb, so that it does not do a fast blink. Anyone want to take a stab at helping me figure out which track I should cut? I've included pictures of both sides of the relay. Alternately if you told me what to test and look for with the multimeter to find the correct track to cut that would work too.

posted_image

I did some more testing of the IC on that board since I can't find a pinout of it. Here are the results with no load and then with fast flash. I used stable and unstable to indicate whether or not the voltage was jumping around. Basically if I can figure out which pin is responsible for sensing a burned out bulb then I can cut the associated track.

1 12v     10v unstable
2 0v     257mV unstable
3 12v     12v stable
4 6v     10v unstable

5 12v      10v unstable
6 0v     12v oscillating
7 12v     12v stable
8 0.745v 1v unstable

Led flashers will blink at a steady rate even with a burnt out bulb typically.

Steady rate, yes. Too fast though. Thats because the IC on the relay measures current drop to detect a bulb burnout and then blibks fast if there is a burnout. In the case of LEDs they draw so little, that circuit is triggered, so thats why i need to find an LED compatible replacement or cut the track on the cicuit board that senses the voltage drop.

@lurch228 Sorry you said LED flasher. I dont have an led flasher. The point of this post is to either find a compatible led flasher or modify my current flasher to get rid of the hyperflash.

Which is what I posted above, the EF29L is a LED Compatible flasher.

@lurch228

The EF29L has 4 prongs
Battery
Ground
Load
Sense

The stock relay has 4 prongs
Battery
Ground
Load (lights)
Load (single dash light)

I might be totally off in my understanding of the wiring diagram of the EF29L but it appears to me that Sense receives a 12v+ signal, not outputting a 12v+ pulse, so you see why the EF29L (or EP29) won't work?

At this point unless I can find a 4 prong with the same configuration, I will need to switch to a 3 prong (CF13, CF14, EP35, EP36) and just wire 2 and 3 together. The other option is disabling the burnout sensor of my current relay by cutting the track leading to that prong on the IC that senses a drop in current.

I'll take the blame for suggesting the EP29. I just noticed it had 4 terminals and said it was LED compatible. I didn't look into the wiring, etc.

You're probably on the right track with a 3 terminal flasher. When I rewired my turn signals, I used either an EP34 or EP35 (don't remember which). The nice thing is, these plug right into a standard H4/9003 headlight bulb harness (pick up at the local auto parts store), giving you a ready-made pigtail. Or, you can even use a standard relay harness, if you want.

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My ex once told me I have a perfect face for radio.

Try this one Which states: Part # AF-01, Bosch 4 pin replacement has extra “KBL” connection for dash indicator.

Adjustable Flasher P/N AF-01

You might want to research this Link:Bosch 4 Pin relay info

OK, before lurch's post I ended up purchasing a CF-13 LED flasher which is a 3-pin relay (+ L -). When I connect the turn signal indicator switch (10 on the diagram) to the load it runs the relay constantly. I can't figure out why this is from the wiring diagram or what I can do to alleviate the problem. When both dash indicator switch and flasher switch are connected the relay just runs which would be annoying.

At this point I could run the relay without the dash indicator but that isn't ideal. Perhaps I could bypass the dash indicator switch and wire directly to the dash indicator since there is only one indicator and not separate ones. Thoughts?

posted_image

I can try lurch's suggestion, but just don't want to keep buying relays.