Electrical Gremlins: Gauges and EFI fuse.. HELP?
10-24-2017, 12:55 PM
#1
Registered User
Thread Starter
Electrical Gremlins: Gauges and EFI fuse.. HELP?
I'm blowing the EFI fuse and the Gauges fuse chronically in the ON position. Hopefully someone can help me out. I've looked at some other users threads, and checked everything they've done, but my problem is different.
- Here is the email I sent today to the auto electrician i made an appointment with for Thursday (10/26). It explains the whole story.
**What perplexes me the most is the fact that I am somehow BRIEFLY getting power to the gauges circuit WITHOUT the fuse even being inserted... but only for a few seconds, then the EFI fuse shorts, and power is lost to the gauges/windows/etc..**
EMAIL:
Hi Ray, Just a recap and some notes from my observations that may or may not help with your own diagnosis:
A month ago i was driving on the highway and a constant rate and the truck shut off. Found that the 15a EFI fuse in the fuse box under the hood was blown. Replaced it, it started up - and got to the end of my driveway blown again. Replaced it, drove around a few miles before it blew again, replaced it and got all the way home, then started checking wires, harnesses, and grounds. I removed the fuel pump, cleaned connections, found no visible wire damage or bad grounds. Truck started up and miraculously had been driving fine.
2 weeks ago, I was driving home and my gauges, power windows, reverse lights and heater blower failed. - 10a "gauges" fuse blew. I have an auxiliary switch that gives 12v directly to the factory reverse lights, and 2-18w led spot lights. When I flipped on the switch, i got power to the circuit. Replaced the fuse, everything was back to normal.
Saturday night i went wheeling on some power lines (don't worry, I washed the truck after) and the gauges fuse blew. Waited till i was off the trail to replace the fuse. Shut off the truck, replaced the fuse, tried to turn the truck back on... no start, and "gauges" blew immediately.
NOW:
Problem 1: Engine cranks, but no ignition. Found that 30a AM2 fusible link fuse was blown, 15a EFI fuse was NOT.
- I replaced the 30a fuse, and the EFI fuse blew in the ON position. 30a fuse has not blown again since. EFI fuse continues to short. EFI fuse is always hot, yet when in the ON position ONLY one of the fuse terminals becomes grounded.
**I've been using a 60w H3 lamp soldered to a broken fuse in place of the problem fuse(s) to check when the short is happening.
- From my interpretation of the wiring diagram in the Hayes manual, I started unplugging things on that circuit.
-unplugged EFI main relay - No Short circuit.
-then started unplugging stuff the relay feeds: Circuit Opening Relay harness, Air Flow Meter, Fuel Pump, throttle Position sensor, both VSVs, EGR, and ECU. The short persists. Also unplugged the noise filter, igniter and igniter coil.
- I did NOT unplug the O2 sensor, however its brand new (couple weeks old), and I inspected the wiring back to the engine compartment. Other things on the circuit (according to the manual) that i havent unplugged include : Water thermo sensor, HAC sensor, air valve.
Problem 2: 10a "gauges" fuse in the drivers kick panel chronically blows in the ON position. One side of the fuse is grounded out (very high continuity with the body).
- Foolishly I replaced the 10a fuse with a 25a circuit breaker fuse (which i bought to test the AM2 fuse problem) before i decided to go for the headlight bulb method, this caused the power wire to the "gauges" fuse to smoke and roast off about 10" of that wire's housing leading up to the fuse box.I repaired that wire - luckily no other wires were damaged.
- Today after I washed my truck, I turned the key to the ON position. The homemade test light was in the EFI fuse, and the gauges fuse port was **empty**, yet the test light did NOT turn on, and the gauges circuit got power (WTF), Gauges worked, windows worked, etc. I turned the key off, then ON, and everything worked again briefly (2-3 seconds), then shut off and the EFI fuse short indicator lit up. Turning on the auxiliary switch to the aftermarket lights no longer powers the circuit like it did the first time the fuse failed, however it still powers the reverse lights.
I have a suspicion that the ignition switch may have something to do with it. The unlock warning switch stopped working recently as well.
- Here is the email I sent today to the auto electrician i made an appointment with for Thursday (10/26). It explains the whole story.
**What perplexes me the most is the fact that I am somehow BRIEFLY getting power to the gauges circuit WITHOUT the fuse even being inserted... but only for a few seconds, then the EFI fuse shorts, and power is lost to the gauges/windows/etc..**
EMAIL:
Hi Ray, Just a recap and some notes from my observations that may or may not help with your own diagnosis:
A month ago i was driving on the highway and a constant rate and the truck shut off. Found that the 15a EFI fuse in the fuse box under the hood was blown. Replaced it, it started up - and got to the end of my driveway blown again. Replaced it, drove around a few miles before it blew again, replaced it and got all the way home, then started checking wires, harnesses, and grounds. I removed the fuel pump, cleaned connections, found no visible wire damage or bad grounds. Truck started up and miraculously had been driving fine.
2 weeks ago, I was driving home and my gauges, power windows, reverse lights and heater blower failed. - 10a "gauges" fuse blew. I have an auxiliary switch that gives 12v directly to the factory reverse lights, and 2-18w led spot lights. When I flipped on the switch, i got power to the circuit. Replaced the fuse, everything was back to normal.
Saturday night i went wheeling on some power lines (don't worry, I washed the truck after) and the gauges fuse blew. Waited till i was off the trail to replace the fuse. Shut off the truck, replaced the fuse, tried to turn the truck back on... no start, and "gauges" blew immediately.
NOW:
Problem 1: Engine cranks, but no ignition. Found that 30a AM2 fusible link fuse was blown, 15a EFI fuse was NOT.
- I replaced the 30a fuse, and the EFI fuse blew in the ON position. 30a fuse has not blown again since. EFI fuse continues to short. EFI fuse is always hot, yet when in the ON position ONLY one of the fuse terminals becomes grounded.
**I've been using a 60w H3 lamp soldered to a broken fuse in place of the problem fuse(s) to check when the short is happening.
- From my interpretation of the wiring diagram in the Hayes manual, I started unplugging things on that circuit.
-unplugged EFI main relay - No Short circuit.
-then started unplugging stuff the relay feeds: Circuit Opening Relay harness, Air Flow Meter, Fuel Pump, throttle Position sensor, both VSVs, EGR, and ECU. The short persists. Also unplugged the noise filter, igniter and igniter coil.
- I did NOT unplug the O2 sensor, however its brand new (couple weeks old), and I inspected the wiring back to the engine compartment. Other things on the circuit (according to the manual) that i havent unplugged include : Water thermo sensor, HAC sensor, air valve.
Problem 2: 10a "gauges" fuse in the drivers kick panel chronically blows in the ON position. One side of the fuse is grounded out (very high continuity with the body).
- Foolishly I replaced the 10a fuse with a 25a circuit breaker fuse (which i bought to test the AM2 fuse problem) before i decided to go for the headlight bulb method, this caused the power wire to the "gauges" fuse to smoke and roast off about 10" of that wire's housing leading up to the fuse box.I repaired that wire - luckily no other wires were damaged.
- Today after I washed my truck, I turned the key to the ON position. The homemade test light was in the EFI fuse, and the gauges fuse port was **empty**, yet the test light did NOT turn on, and the gauges circuit got power (WTF), Gauges worked, windows worked, etc. I turned the key off, then ON, and everything worked again briefly (2-3 seconds), then shut off and the EFI fuse short indicator lit up. Turning on the auxiliary switch to the aftermarket lights no longer powers the circuit like it did the first time the fuse failed, however it still powers the reverse lights.
I have a suspicion that the ignition switch may have something to do with it. The unlock warning switch stopped working recently as well.
10-25-2017, 05:23 AM
#3
Registered User
Thread Starter
ah nevermind. After the engine swap i routed the bundle of wires that go down to the 02 sensor on the passenger side too close to the EGR and it melted through. I cant believe i didnt see it earlier. Its always SOMEthIng simple.
