Archived 96, All Dash Instr. Stuck ON, No Tach, Low Volts

[LBrazdys]

Oo.



ITS THE TRANS RELAY CIRCUIT!!!!!!!!!!!

I was experimenting with differnt combinations and got the ALT to charge and all of the lights work properly.



The 20 AMP fuse link feeds the trans relay circuit. The relay itself is ok... ... means that there is either a short at the selinoid, the selinoid itself or I hope not the ground path at the PCM. If you leave all the relays in place at the PDC, as soon as you turn the key you blow the 20 AMP fuse link in the RUN position. Take the TRANS relay out, replace the 20 AMP fuse link and you will get charging, guages and tach back.



All I did before all this happened was change the trans filter. Could the selinoid be jammed shut??



Cant beleive this circuit can cause so many problems!!!!!!!!!!



At least the tach, guages and charging (13. 7v) circuit work. Does anyone know what would happen if I would drive the truck with the trans relay pulled out of the PCM. I have an 47RE auto, I am assuming the OD wont work.



Also, asyone with a jumpy tach and ammeter, the following combination of relay/fuse failures will giver you said condition.



Blown 20 amp fuse link with out trans relay in PDC.

 

[DavidC]

I do not think I would drive with out the relay. Time to pull the pan after a visual of the wiring going to it. Probably pinched a wire internally. If it is internal the next big question is what to use to repair the wire. A jammed solenoid would not blow a fuse. A shorted one will though.



Dave

 

[p-Bar]

Pullthe wire on the soleniod to trouble shoot if it is that.

 

[LBrazdys]

PROBLEM SOLVED!!!!!!!!!!!!!!!!!!



Pulled pan... ... ... ... ... . replaced AZONE cork gasket (what junk... ..... leaked brand new) with OEM. Re-routed some wires in the pan tha looked out of place... ... ... ... . cleaned the case connector... ... ...



Got my scan tool and it showed no codes... ... ... ... somewhere I read that it wouldnt throw a code on a shorted circuit. Anyway, I cycled the key and got 3 + 5 + 5 flashes on the idiot light. Dont know what that means.



All is well, charging, lights and instruments are ok... ... ...

I pretty much now know every nook and cranny on this beast after dealing with this gremlin.



So the moral of the story is... ... ... ... ..... if your popin 20 amp links, have a call to ac without the switch call and loose all your guages... ... ... ... ..... check the trans pan.



THANKS TDR

 

[DavidC]

Aren't computerized vehicles fun. Glad you found the problem.



Dave