'97 NAS D-90 electrical short, ideas?? (please!)
'97 NAS D-90. Fuse #17 (15amp - shift solenoid, brake lights, turn signals, engine immobiliser) keeps blowing. Fuse started blowing every once in a while and now blows as soon as the key is turned on.
Recent work on the truck included replacing two A/C hoses (cracked), new A/C compressor (tech said it was bad because it kept blowing out the overpressure valve??, said the expansion valve needs replaced, too but haven't gotten there because I'm beginning to doubt his "replace it all" diagnostic abilities), new A/C receiver drier (had a part machined to mate the original trinary switch to the new drier - original drier no longer available).
After removing the center console and A/C vents found some melted wires. The relay farthest right (towards the passenger side - yellow 4 prong) had a grey wire w/black stripe (blade 30 on the relay) melted all the way into the engine compartment and a melted green wire (blade 87 on the relay) going to a header joint.
With the suspece relay removed (I did replace the relay with same fuse blowing results), I can apply power through fuse 17 with no problems. Brake lights, turn signals, shiftlock solenoid all work.
With the relay in and key on (with no fuse in #17) I get power to blade 85 which is a black wire with a red stripe.
My understanding of relays is that blade 30 (gray wire with black stripe) should be the constant power, blade 85 (black wire with red stripe) ground, blade 86 (yellow wire with black stripe) power in to activate the relay, blade 87 (green wire) the power out after "connecting" to blade 30. In my case, seems like 30 and 87 are backwards and 85 shouldn't be "hot" when the key is turned on??
From the wiring diagram I see a gray wire with black stripe going from the ECU to the condenser fan relay. I haven't traced the melted wire from the relay all the way, but am assuming this is it. I can apply power to the condenser fan and it runs fine. Can't tell where the black wire with red stripe goes but think from the diagram it goes to the A/C compressor clutch relay.
My eyes are bleeding from the wiring diagram, my truck is in pieces, and I'm stuck. Thoughts/suggestions VERY welcomed at this point. Thanks in advance!!