1989 Bronco XLT, 351W, C6
Thinking there's a short, but how to trace it?
Also, where do I find the fusible links I would need to replace the ones on my Bronco?
Thanks in advance for your help.
Thank you for this information!Yo CO,
FUSIBLE LINKS @:
Sherco's quality selection of Fusible Links for General Motors and Ford Starter Solenoid and Fusible link wire in 10' lengths available in 18g 16g 14g 12gwww.sherco-auto.com
Look for direct shorts to a GROUND FOR EACK FUSIBLE LINK
A, F, G, J, L, M, N, P, W & Y Location in Wiring Diagram in an 89; Fusible Link A-Brown 18ga to Rear Window Defroster; W-Blue 20g to Fuel Pump Relay; N-Blue 20g to EEC Power Relay; F-Blue 20ga to Trailer; Y-Blue 20ga to N.C.; L-Brown 18ga to ?; M-Brown 18ga to ?; G-Blue 20g to Exterior Lamps, Trailer; P-Blue 20ga to ?; & J-Green 14ga to Alternator
Source: by Seabronc (Rosie, Fred W) Rest in Peace Friend...
Parasitic Current Drain Test"...you should be able to trace the "parasitic draw" on the battery in the normal way. Pull the (-) cable off & put an ammeter inline set to the 10A range (or higher if possible) to see how much current is being pulled out of the battery with the key OFF, the doors SHUT, & the hood light bulb REMOVED. Make sure absolutely NOTHING is turned on anywhere on the truck. If it registers 0 or below the meter's next range, switch it down a range until it shows some useful numbers. If it ends up being below 0.5A (500mA), then replace the battery. If it's above that, start by disconnecting all the alternator wires & see if the reading drops under 0.5A. Then move to the fuse block & pull them 1 at a time until there's a significant drop in the reading. That's the circuit that's draining the battery. Follow it to find the problem..."
Traced the dead short to the 12v power line for the fuel pumps (pink/black). It was actually melted the full length of the chassis harness. I had another harness from a donor, so I swapped it out and replaced all the fusible links at the battery. I was concerned when the harness read continuity between the power wire and ground but realized that the pumps would read continuity so I fired it up. The fusible link for the fuel line started overheating again. Does anyone know what the impedance through each of the fuel pumps is supposed to be? The original high pressure pump (on vehicle when meltdown occurred) reads 2ohms--I replaced it for the donor which appears to have come from CarParts.com--the "new" pump reads 17.5ohms. I haven't checked the impedance across the in-tank pump yet, but if any of these values are too low, it might explain the over-amperage I'm witnessing at the fusible link.Thank you for this information!