relay question

[DodgeFreak]

Is there a relay that will work with low voltages say .5-5volts???

[Philip]

Ok what are you controlling?

Total amp draw of loaded circuit?

Why only a 5 volt signal?

Most of the time relays you find for that low of voltage signal are PC board type relays. A normal 4/5 pin relay I have never seen one for that low of signal voltage.

Now there are electronic relays that can handle that low of voltage. They can be had to switch eather AC/DC power circuits.

Here is an example of one.,

http://www.grainger.com/product/CRYDOM- ... ?$smthumb$

[DodgeFreak]

I want to control lock up on a 98 47re with the tps. The computer kicks lu off when you back out of the throttle. I was thinking I could do that with a relay. Not only would it be like factory but it would be a safety feature where it wouldn't lock up with out throttle input.

It has a manual valve body in it but he wants it some what driver friendly incase his wife drives it, I'm going to run the od and lock up off pressure switches and toggle switches but In case they forget to switch lock up off it will automatically switch it off.

[PToombs]

You don't need a low voltage relay for that, I think you are overthinking it. You are basically putting in a mystery switch that cuts itself off. Put in a regular relay with the LU circuit Teed into on the 30, and 87 terminal to ground. Then put power to the 85 and 86 goes to what ever triggers it, then to ground from the trigger. Clear as mud? If not I'll see if I can hallucinate it better for you.

[ellis93]

If you run those switches on gov pressure port it'll do as you want anyhow. If the gov drops pressure then the psi switch will drop the gear/converter. That's the way mine does. My only problem is when I manually lock the tcc at lower speeds (lower psi) and forget about it when stoping (ground is tied in with the brake switch). Makes for some excitement at a stop sign or red light

[DodgeFreak]

You don't need a low voltage relay for that, I think you are overthinking it. You are basically putting in a mystery switch that cuts itself off. Put in a regular relay with the LU circuit Teed into on the 30, and 87 terminal to ground. Then put power to the 85 and 86 goes to what ever triggers it, then to ground from the trigger. Clear as mud? If not I'll see if I can hallucinate it better for you.

Well that's my plan.....I think ???

If you run those switches on gov pressure port it'll do as you want anyhow. If the gov drops pressure then the psi switch will drop the gear/converter. That's the way mine does. My only problem is when I manually lock the tcc at lower speeds (lower psi) and forget about it when stoping (ground is tied in with the brake switch). Makes for some excitement at a stop sign or red light

My plan is to....Run a 44psi to control od a 50psi to control lock up, also tie into it to manual lock up od and lock up, and an open to disable it. Run a 20-25 psi switch as a fail safe for both. I was wanting to wire in a relay tied into the tps that way if they are costing down a hill it will unlock and I think it would be easier on the trans. The tps has an input of 5vs range from .7- what ever?? I didn't think a standard relay would trigger at 1-4 volts. Is that clear as mud???

[oldestof11]

Ask Begle. Sounds like something he'd do

[PToombs]

I don't think a relay will trigger that low, if you have one laying around you could try it.
I wouldn't want it to unlock going down a hill. I have a 47RE in my '97 so I have some experience with how it functions. I know on the highway at 70 if I touch the brake or coast too far it unlocks, then it has to think about it and acts funny until it locks back up, or sometimes doesn't lock at all. I prefer to manually lock it to prevent those issues. Like Ellis said, it's fun when you come to a stop and you forget you have it locked. I understand what you are trying to do, make it user friendly for the uninformed masses, but I think you need to plan a little more 1st. Or swap to an RH trans.

[DodgeFreak]

I don't think a relay will trigger that low, if you have one laying around you could try it.
I wouldn't want it to unlock going down a hill. I have a 47RE in my '97 so I have some experience with how it functions. .

Hence the question about finding a relay that will trigger that low.

47re's are all I've really messed with.. I know in the 99 that I rebuilt would automatically unlock as soon as you backed out of the throttle If you would just barely stay into the throttle it would stay locked. I don't remember in the 98 tbh. Plus lockup would be commanded by the tps so it wouldn't hunt for lock up, once it hits 1.5 volts or what ever its set it at, it would automatically lock back up. there wouldn't be any computer input.

Switching to a RH is out of the question, I'm not messing with getting a new drive shaft and what not plus it wouldn't change my issue, I'd still have to manually control lockup and OD. The other biggest thing for tps controlled lockup is for when he's racing and it's locked up and at the end of a run he doesn't have to remember to flip lock up off before he backs clear out of the throttle, I'm already afraid that the input won't last.

[Philip]

The one concern I would have with using the TPS for that control. The TPS only sends a reference signal to the PCM. The relay your wanting to use doesn't use much power for the pull in coil. But is the TPS capable of standing an actual voltage draw threw it?

A mechanical switch rigged to the throttle pedal like a jack brake idle switch would work. You could mount the switch to trip at what ever throttle position you wanted. You would be using a full 12 volts for it. No special relay needed.

[PToombs]

I had to grind the holes in my TPS to twist it to adjust the voltage to get a sweet spot for shifting, OD and LU. Plus the cable adjustment. How about a potentiometer mod instead of the TPS? Set it where you want and let it go.
IIRC, the RE and RH are basically the same except for the valve body, so the shafts are the same.
I think Philip means like an exhaust brake switch. That would work good too.

[DodgeFreak]

I think you are misunderstanding me or I you. I thought mentioned it (didn't find it maybe some place else) but this 47re is going into a 98 truck, also it has a Full Manual valve body in it. No gov solenoid used. Even if it was an RH It wouldn't matter I would be in the same boat controlling lock up and OD.

I know the shafts are the same between an RH and an RE...My point about the shafts is He will be drag racing the truck down the 1\4 and at the end of a run if he doesn't Unlock the Tq before he backs out of it or if he down shifts with it locked up there will be a lot of stress on the stock input. If I wire lock up based off throttle input whether it be with the tps or a switch and with a pressure solenoid then he doesn't have to worry about shutting off lock up when he backs out of it.

[DodgeFreak]

The one concern I would have with using the TPS for that control. The TPS only sends a reference signal to the PCM. The relay your wanting to use doesn't use much power for the pull in coil. But is the TPS capable of standing an actual voltage draw threw it?

A mechanical switch rigged to the throttle pedal like a jack brake idle switch would work. You could mount the switch to trip at what ever throttle position you wanted. You would be using a full 12 volts for it. No special relay needed.

are they a switch with a long spring like thing sticking out or something better?? I'll do some digging. I've thought about using a brake switch or something also.

[Tacoclaw]

Maybe helpful to you?
5v control, 30v relays, $10 to see if it'll work.

http://www.amazon.com/gp/aw/d/B0057OC5O ... Y200_QL40#

[DodgeFreak]

Just an update.....I thought of this along time ago and forgot to mention it, but Its kind of hard to set up OD and LU on pressure switches when you have the Gov. solenoid unhooked since its a manual valve body. I thought of it before I started running lines and wires lol.