1986 Ford Thunderbird 5.0 No power to Computer/EEC relay


New Member
Jun 11, 2018
Oakdale, CA
1986 Ford Thunderbird 5.0 Elan with no power to EEC relay and subsquently no power to computer, no dash lights, no signal to fuel pump relay, and injectors not firing. Cranks strong, spark checked out firing normally. Jumped fuel pump relay and fuel pump primed and has good line pressure. Relay has power but is not getting signal from Computer to turn on. Checked EEC power relay and only getting 0.05V on each pin. Figured it was a bad fusible link between the EEC relay and battery so i checked all the fusible links off the starter solenoid and they all checked out besides one closer to the wiring harness that is not connected to the starter solenoid had the same 0.05V. I'll have to check tomorrow but i believe this fusible link is the one shown on the top of my attachment in dark blue through a 20g link and into black and orange wires. Should i replace the fusible link to see if i get power to the EEC relay first or look for what popped it in the first place? Thanks in advance, Tanner.


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New Member
Jun 11, 2018
Oakdale, CA
Checked for power at pin 1 on the computer today and sure enough, only getting .1 volts. Could. I bypass the broken power wire completely to get the car home?


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SN Certified Technician
Mar 10, 2000
Dublin GA
Keep in mind that the wiring for an 86 T-Bird may not be like one for a Mustang of the same year. I am very familiar with the diagram you posted and while it is accurate for a Mustang, it may not work for a T-Bird. Get a Chilton manual for your car and check out the wiring diagrams in it.

You ether blew the fuse or fuse link for the ignition coil/EEC relay side of the KAM keep alive voltage. You need to find out what caused the fuse link to blow and go open circuit. Something in that circuit shorted power to ground and caused the fuse link to blow.
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New Member
Jun 11, 2018
Oakdale, CA
Just jumped the ECU pin 1 "KAPWR" with a 18gauge wire with 30amp fuse (all i could find) directly to the battery positive and nothing still with key on. The wire started smoking after 30 seconds... could this be a bad ecu or some sort of short to ground? Really could use some advice here on where to go next. I tested pin 40 for ground before jumping and couldnt find a resistance but pin 60 had resistance. Bad wiring or bad ECU?


Founding Member
Nov 13, 1999
Palm Beach Gardens, FL
Running the jumper the way you did may be back feeding. Bad idea!
KAPWR = Keep Alive Power
This only keeps stored codes in memory.
Main power is pin-37
You need to find out why the EEC relay is not working.

Your other symptoms could indicate the ignition switch.
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