Fuse or Relay for 700R4 lockup power supply?

Know how to wire the 700R4, using the ecm for lockup and brake for release but half of the forums indicate using a relay for ****** lockup power..and some indicate using a only a fused line.

Looking at a GM wiring diagram....only see fused line power.

What do you recommend..Fuse by itself or fuse relay setup?

 

i used a relay with my 200 4r in my 36 then added a switch so i could manualy cont troll lock up

 

richbud

Thanks for the response..sure would like to run it via a fused line without relay. I see some diagrams where they use the relay only to disconnect the "constant power" (ie unlock) the solenoid.

I always considered that the relays were intended to supply power when activated. The 700R4 has constant power to the solenoid and only locks up when it is hydraulically grounded inside, the brake pedal opens (interrupts) the power circuit.

A lot easier to just open the circuit via the brake pedal...

 

Or go this route:http://www.jegs.com/i/TCI/890/37660...&cagpspn=pla&gclid=CJmNv8jvnrYCFYKDQgodVBMAlQ

 

Just want to know if I power the solenoid without a relay.

 

The guy who wired my lockup used a relay, dont recall whether it was a "normally open" or a "normally closed" type.

All I can say is it works fine the way it is.

 

fiftyv8

Thanks for the response…not trying to be argumentative with this post…but:

Trying simplify the wiring in my project, already have relays for the fan, headlights, fuel pump etc. and (yes) could run a trans relay –however- just want to know if it would be OK to run just a fused power feed to the trans (without relay).

Ed

 

Relays are used in high amp situations.

 

Ecms use micro relays on the circuit board
Everything is a relay

 

That's only one of many uses for a relay, and not the reason they are used on a lockup trans. They prevent power feed back, multiple trigger signals, reversing polarity, tons of uses on our cars.

To the op, if you use a relay or not, the same power source will go to the trans. It's up to you to fuse it or not. Most aftermarket kits use a relay to unlock the converter with the brakes. The relay keeps the brake lights from being activated by the trans power. If you want a simple manual system, use a manual switch to lock/unlock the trans.

 

The brake lights are on a separate brake pedal switch (normally open), the trans wiring is isolated. You are correct most after market kits use a relay to "unlock"..but I'm using all OEM GM parts, brake pedal, brake switches, ECM, trans etc.

Thanks .. Getting closer!

 

Then wire it like GM engineers did for the donor application and future simplicity's sake. The ECM will or should tell a scanner what it thinks it is installed in. It should be wired like that.

 

31Vicky

Thanks...going that route...the confusion is with the wiring diagrams posted all over the Internet, the majority of which deal with manual & by p*** lockup wiring. As you said..the factory setup is less complicated.