Trans kickdown relay debugging
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From: Boulder Creek, CA
Duh me.
Fuse #10.
Sorry bout that...left it there and here..for future idiots that should search.
And thats not it..cuz I have the rest of the devices that this fuse services...grr.
Fuse #10.
Sorry bout that...left it there and here..for future idiots that should search.
And thats not it..cuz I have the rest of the devices that this fuse services...grr.
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From: Ball Ground, GA
Power from the 15 bus (ignition switched power) flows to Fuse #10; from Fuse #10 to Terminal B14; from B14 on a black/violet wire to the kickdown switch.
If you have no power at the kickdown switch, there is no point in checking any further until you get that fixed.
Terminal B14 will be the next-to-the-top terminal on the left side of Plug B, which is the 2nd plug from the left end. If there is no power on B14, pull the Central Electric Panel and find the disconnected/broken wire between B14 and Fuse #10. It will be gray...
If you have no power at the kickdown switch, there is no point in checking any further until you get that fixed.
Terminal B14 will be the next-to-the-top terminal on the left side of Plug B, which is the 2nd plug from the left end. If there is no power on B14, pull the Central Electric Panel and find the disconnected/broken wire between B14 and Fuse #10. It will be gray...
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From: Boulder Creek, CA
Power from the 15 bus (ignition switched power) flows to Fuse #10; from Fuse #10 to Terminal B14; from B14 on a black/violet wire to the kickdown switch.
If you have no power at the kickdown switch, there is no point in checking any further until you get that fixed.
Terminal B14 will be the next-to-the-top terminal on the left side of Plug B, which is the 2nd plug from the left end. If there is no power on B14, pull the Central Electric Panel and find the disconnected/broken wire between B14 and Fuse #10. It will be gray...
If you have no power at the kickdown switch, there is no point in checking any further until you get that fixed.
Terminal B14 will be the next-to-the-top terminal on the left side of Plug B, which is the 2nd plug from the left end. If there is no power on B14, pull the Central Electric Panel and find the disconnected/broken wire between B14 and Fuse #10. It will be gray...
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From: Boulder Creek, CA
Yannow, I never checked for 12v from the under pedal plug, but I have 12v at B14, and at the kickdown switch..and when I press the switch I get 12v on the other side as well.
When I trip the KD switch, I get 12v at terminal 30 of the relay plug on the CE panel..so thats a good return path.
Maybe I should shop out a relay...
I have the relay apart, and its very clean...no issues mechanically inside it at all.
SO..if the kickdown switch mod would force this relay open, because without that 12v, the relay is normally closed..with it, it opens.
With the relay case open, a visual inspection with the KD switch pushed..shows no visible opening of the relay.
So..force the relay open and see what it does?
We'll try that...since thats all this 12v feed to the thing does at terminal 30..is energize the coil and open the contacts.
When I trip the KD switch, I get 12v at terminal 30 of the relay plug on the CE panel..so thats a good return path.
Maybe I should shop out a relay...
I have the relay apart, and its very clean...no issues mechanically inside it at all.
SO..if the kickdown switch mod would force this relay open, because without that 12v, the relay is normally closed..with it, it opens.
With the relay case open, a visual inspection with the KD switch pushed..shows no visible opening of the relay.
So..force the relay open and see what it does?
We'll try that...since thats all this 12v feed to the thing does at terminal 30..is energize the coil and open the contacts.
Last edited by Speedtoys; Feb 25, 2011 at 11:50 AM.
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From: Ball Ground, GA
"So..force the relay open and see what it does?
We'll try that...since thats all this 12v feed to the thing does at terminal 30..is energize the coil and open the contacts. "
Ummm - no.
The kickdown relay does not cause the transmission to kick down. The 12 vdc thru the switch under the throttle provides power to the contacts in the relay, not to the coil. That power on Terminal 30 flows thru the NC (Normally Closed) relay contacts to the kickdown solenoid on the transmission.
The function of the kickdown relay is to momentarily open those NC contacts at max RPM. This drops the kickdown solenoid to normal operation, causing the transmission to instantly upshift. As soon as the RPM level drops in the next gear, the relay drops out and the NC contacts close, putting the transmission back into kickdown mode.
With the car in a quiet place, pull the kickdown relay and locate Terminal 87a in the socket. Use a jumper to momentarily apply and remove 12 vdc to 87a. Each time that you apply/remove the power, you should hear a "click" from under the car. If you hear no click, either the circuit from 87a to the solenoid is broken, or the solenoid is faulty.
We'll try that...since thats all this 12v feed to the thing does at terminal 30..is energize the coil and open the contacts. "
Ummm - no.
The kickdown relay does not cause the transmission to kick down. The 12 vdc thru the switch under the throttle provides power to the contacts in the relay, not to the coil. That power on Terminal 30 flows thru the NC (Normally Closed) relay contacts to the kickdown solenoid on the transmission.
The function of the kickdown relay is to momentarily open those NC contacts at max RPM. This drops the kickdown solenoid to normal operation, causing the transmission to instantly upshift. As soon as the RPM level drops in the next gear, the relay drops out and the NC contacts close, putting the transmission back into kickdown mode.
With the car in a quiet place, pull the kickdown relay and locate Terminal 87a in the socket. Use a jumper to momentarily apply and remove 12 vdc to 87a. Each time that you apply/remove the power, you should hear a "click" from under the car. If you hear no click, either the circuit from 87a to the solenoid is broken, or the solenoid is faulty.
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From: Boulder Creek, CA
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From: Boulder Creek, CA
Tranny fluid is way low, gonna solve that first, before I get to the solenoid..which I did find, and only has 1 wire going to it..guessing it grounds via the tranny itself.