real simple problem, but I can't find the solution.

You should use any 100...1000V silicon diode e.g.:1N4001...4007. This diode always needed when the relay drived by any semiconductor.(protect against rverse inductive voltage)
2. Yes, correct. (the resistor give log. low level when no incoming signal)
3. Yes, for better reading the "k" is in "comma" position.(3k3=3.3k)

Sebi said:

You should use any 100...1000V silicon diode e.g.:1N4001...4007. This diode always needed when the relay drived by any semiconductor.(protect against rverse inductive voltage)
2. Yes, correct. (the resistor give log. low level when no incoming signal)
3. Yes, for better reading the "k" is in "comma" position.(3k3=3.3k)

Click to expand...

oh, BTW, is this a good capacitor for my setup?
https://www.mouser.com/index.cfm?handler=displayproduct&&lstdispproductid=303345

oh, and what transistor?**broken link removed**

is this a good capacitor for my setup?

Click to expand...

Any capacitor rated above 16V will do. Value is not critical (0.1 - 1.0uF).

oh, and what transistor?

Click to expand...

BC327, BC328, BC556, BC557, BC558, BC559, PN200, 2N2907 or 2N3906 are all OK. There may be others, too - this is a very general purpose application.

Klaus' circuit gets my vote !
It took me a while to get my head around this, even after drawing it,
I was convinced some steering diodes would be required, but no!

This should work just 'as is'

Any car junk yard will yeild a fist full of relays that can do this, or an auto factor shop.

cool, thanks guys. I'll try out what I can and I'll get back in a few weeks to show you guys how it came out.

BTW, here's what I'm working on:
**broken link removed**
That is not my car, but I bought that piece (with the 2 round lights) off of this guy and it will be going on my car shortly (after I paint it). My car is in the www below.

Thanks yall.

Howdy!

Hi all,

New to this list, and randomly perusing threads.

Klaus, I like your 2-relay circuit/solution.

1997GA16DE, something I'm confused about ... if you press the brakes, the light goes on. If you turn the blinker on, then the bulb flashes. If you do both, the bulb still flashes, but 180-deg out of phase with the blinker signal. Any reason for the out-of-phase requirement? I'm wondering why not just state the design as blinker takes priority over the brake? This would eliminate the XOR requirement, though the solution may not be any simpler that those proposed. Just curious.

Cheers,
-Neil.

correct, the rear blinker will be flashing opposite to the front blinker bulb, but only when I have the brake pressed. I agree it would be better to have it flash like normal all the time but that would require more work than I'm really up to doing (the blinker's signal is not constant and there is nothing on it that is constant except at the switch). Nevertheless, it still blinks and that's all that matters to me (and the policia).

I may consider looking at the wiring diagram in my haynes manual (Well known automotive book that breaks down every electriclal and mechanical system in just about every car model). Maybe I can find a constant signal from the switch that can cancel out the brake (using a normally closed relay). The only problem is that the left signal, the right signal and the hazzard lights each have their own switch, relay, and blinking unit in my car, I would have to tap into my hazzard switch as well to ensure the hazzards will work correctly.

Thanks for the idea tho, I may decide to use it.

BTW, can someone give me a place to find a N/C relay with a 12V coil?

You're not really looking for an N/C relay, but an SPDT relay, and then just use the N/C contacts. Try www.jameco.com part # 129349.

Cheers,
-Neil.

you know what, sorry for going through all that work, but I think I figured out a better way. I went to my cars exterior lighting wiring diagram and I figured out a way to make the signal blink normally and solve my problem. I can hook a second signal into my blinker switch. When I flick on the left signal, it will trigger an N/C relay to cut off the signal to the left outer brakelight (and the signal will blink normally). When I do a right turn, it will cut out the right outer brakelight allowing the blinker to blink in its place.

Thanks for all the help and ideas, it just takes some time until the right solution comes to you .

ok, I almost got this done. Here's what I decided doing:
**broken link removed**
this will cancel the brake signal when the blinker for that side is on, the blinker signal can take over illuminating the bulb until I turn off the blinker switch.

I ran into a small snag right now, the wires (between the front and rear relays) run under the door sill along the driver's side. Once they get to the trunk, both wires go to the back of the car where the taillights are. Once the wires are at the back of the car, the passenger one needs to run all the way across the trunk to the other side, so naturally, the passenger side wire needs to be a bit longer. When I finished running the wires, I tested the blinkers out:

First test, nothing worked...oops, forgot to hook up the harness ... :roll:
second test, drivers side worked, passenger side did not..uh oh.

I then proceded to check the passenger side ground, it was fine, I checked the rear relay, and it was great. I knew the front relay already worked from an earlier test. Next, I turned on the passenger signal (nothing happened) and I touched a new ground to the long wire to see if it works. When I touched it, the front relay activated and when I lifted up, both relays worked. I turned the blinker off and then on again and once again, nothing...Found my problem.

apparently the resistance from the 2 relays and the long wire is just a tiny bit too much to activate the relays. I can activate the front relay alone even through the long wire, but not both at the same time. Also, the resistance is just a bit too much to activate the relays, but once I do get them on they will stay on as long as the switch is on.

I would assume the wire is just a few inches to a foot too long, I am using 18awg copper wire and I really hate to route a new wire in b/c it requires me to remove the back seat again. what should I do? I tried making the ground at the end of the circuit better, but it still didn't help.

From the diagram, you appear to have 2 relays in series. Therefore, they should be 6V relays, not 12V. If you use less than the rated voltage on a relay, you can have problems of unreliable activation.

ok, what do you recommend from here? I don't have any other relay. All of th relays are the same, they ar the 5 point relays that are both N/c and N/O.

The recommodation is very simple, you don't connect relays in series.
Instead, connect them in parallel then they still operate both at the same time but each gets the full 12Volts.
Connect on coil side of EACH of the 4 relays to ground.
Connect the other coil side of each PAIR together and then to L or R of the switch.
Klaus

Klaus said:

The recommodation is very simple, you don't connect relays in series.
Instead, connect them in parallel then they still operate both at the same time but each gets the full 12Volts.
Connect on coil side of EACH of the 4 relays to ground.
Connect the other coil side of each PAIR together and then to L or R of the switch.
Klaus

Click to expand...

yea, I just did that. Yesterday, I was thinking about it and I said, I could just split the incoming signal and have each go to one relay (or parallel). I was like "..duh".