Turn Signal/Hazard Flasher Relay

[davegonz]

I'm trying to figure out why my turn signals don't work and decided on replacing the stock 1974 relay with a new one that was in my parts bin. The new one has a pigtail with a ground wire and two terminals (B and L). The old one, Toyota 81980-31030, has three terminals (B, L, S). Can I use the new one and just combine the two wires from the old L and S terminals?

New one:

 

[davegonz]

Stock:

 

[xtiaan2000]

Do t know nothin about nothing, but could one of the three be a ground?

 

[davegonz]

There's a ground on the new flasher. On the old one, I think it was grounded through the metal cover and mounting bracket.

 

[Coolerman]

If you could post (or send me) a clear schematic of the FJ55 I might be able to help. The only schematic I have is unreadable.
Just guessing but three terminal flashers usually are as follows:
B = +12V
L = Load (lights)
S or L2 = secondary load (sometimes this is for the dash indicator lights)

 

[npulver]

I was going to say the same as coolerman, Will have to see how the relay trips to see if you can use it properly. So if you have a schematic of both that would be great (guessing the new one might have it printed on the side)

 

[davegonz]

If you could post (or send me) a clear schematic of the FJ55 I might be able to help. The only schematic I have is unreadable.
Just guessing but three terminal flashers usually are as follows:
B = +12V
L = Load (lights)
S or L2 = secondary load (sometimes this is for the dash indicator lights)

Coolerman, the only schematics for the 55 I have been able to find are the ones on your site. They both show only two wires going to the flasher relay (B and L) with the ground coming off of the relay housing/bracket.

 

[davegonz]

Here's a pic of the internals.

 

[Coolerman]

I have seen the three terminal flasher in another manual. I'm trying to find it now... I would use jumpers to connect B to B and L to L and see what happens.

 

[J Mack]

This is for a 1975 not sure if it will work for you.

Seams like I tried a two wire on mine and it didn't work so i just cleaned up the contacts in the old one and reinstalled.

 

[davegonz]

That works @J Mack ! Thanks for posting that. It clearly shows three wires instead of two. Can you clarify what the labels are on the flasher (B, L1, L2?)?

 

[J Mack]

Can you clarify what the labels are on the flasher (B, L1, L2?)?

Yes, 1975 shows,
B - GW
L1 - G
L2 - GL

1974 shows,
L1 - GL
B - GW
L2 - G

Too small for a photo.

 

[davegonz]

Excellent. I have a 74, so those colors make sense. Thanks J Mack.

 

[Coolerman]

Found this schematic in a 1975 manual. It is for USA and Canada...

This schematic shows the three terminal flasher.

This is my theory about how the three terminal flasher works. Lets assume the flasher cycles once per second. L1 and L2 are probably NO and NC contacts on a relay. As the flasher cycles, power is applied to first L1 then taken off L1 and applied to L2. Since L2 is tied back to L1 through the Hazard switch, the frequency of L1 would be TWICE a second going to the turn signal. However if you turn on the Hazard Switch this breaks the loop back to L1 meaning that the Hazard switch will flash the lights once per second.

Can someone confirm this is how it works in real life? If it does then you can just connect B to B and L to L and both Hazards and Turn signals will flash ONCE per second. If this is not how it works I need to go back and rethink this.

 

[davegonz]

This is what I figured...L2 powers the turn signals until the hazard switch is engaged. That's when L1 takes over and that powers all of the lights. Maybe....

So, I should replicate this by using two of these newer relays? Or, I can just combine L1 and L2 to be powered off of the single L terminal on the newer relay?

 

[Coolerman]

Well, if my theory is correct, you can combine the L1 and L2 to L, but your frequency will be 1/2 what it was for the turn signals.

 

[davegonz]

Easy enough to try. I'll see if I have time tonight after work.

 

[davegonz]

I tried combining the two L-terminals and got mixed results. The turn signals worked fine, but once I switched on the hazards, I got nothing.

I did notice that the two solenoids in the old relay were electrically tied together via a capacitor. Is the capacitor (draining/charging) what generates the flashing/blinking?

 

[J Mack]

Your results mirror mine.

My blinker/hazards would work every other day and one of the key reasons I decided to update my wiring. I wasn’t smart enough to come up with a permanent solution for the aging factory parts but I will say that the bulk of my issues were ground related.

Good luck!

 

[Megadoomer]

I'm having lighting issues now. When I hit my break my running lights turn on also when I use my left blinker. I noticed the rear left marker light was blinking with the left blinker so I think there is a loop at that light. I can wire from the start, but to diagnose someone else's spaghetti is tough.