Fuse #15 blowing
Thread Starter
Heel & Toe
Joined: Apr 2013
Posts: 19
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From: VA
Fuse #15 blowing
0 continuity fuse to ground when all 4 O2 sensors (2 sims, 2 sensors in fact) are disconnected. As soon as *anything* is connected, either sim or o2 sensor then the + pins have continuity to ground. Is this normal, if so, how do I find the fault?
Having serious trouble pinpointing what is causing the fuse to blow repeatedly.
Hope this description makes sense.
Having serious trouble pinpointing what is causing the fuse to blow repeatedly.
Hope this description makes sense.
Last edited by catfishbear; Jun 4, 2017 at 05:03 PM.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The O2 sensor harness and connectors are in a very close proximity to the exhaust and frequently get melted or damaged. I would start by unwrapping the harness and examining the wires and connectors.
I am going to supply you a schematic so you can more effectively troubleshoot. Your explanation of the issue is confusing.
When everything is DISCONNECTED, do you have 12VDC wires to ground?
The circuit that you are concerned with are the O2 Sensor HEATER CIRCUIT wires.
I am going to supply you a schematic so you can more effectively troubleshoot. Your explanation of the issue is confusing.
When everything is DISCONNECTED, do you have 12VDC wires to ground?
The circuit that you are concerned with are the O2 Sensor HEATER CIRCUIT wires.
Thread Starter
Heel & Toe
Joined: Apr 2013
Posts: 19
Likes: 0
From: VA
Thank you, I had printed out said schematic and used it in my troubleshooting over the weekend. My apologies for the poor description. I will try again.
If I disconnect every O2 sensor (and sim) from their respective connectors, there is no continuity to ground from the #15 fuse. If I connect any one of the 4 sensors, then the #15 fuse has continuity to ground. I have physically inspected all wiring that is accessible, pulled off the fender, removed the battery and PCM to access the harness but have found nothing apparently shorting to ground.
I suspect my next best option is to put everything back together and connect only 1 sensor at a time, starting the engine and waiting for the fuse to blow. How long does the engine have to run before O2 heaters are turned on? Does the car have to drive or can it idle in the driveway?
Temps have been 80-90F here lately so I'm guessing this may affect it.
If I disconnect every O2 sensor (and sim) from their respective connectors, there is no continuity to ground from the #15 fuse. If I connect any one of the 4 sensors, then the #15 fuse has continuity to ground. I have physically inspected all wiring that is accessible, pulled off the fender, removed the battery and PCM to access the harness but have found nothing apparently shorting to ground.
I suspect my next best option is to put everything back together and connect only 1 sensor at a time, starting the engine and waiting for the fuse to blow. How long does the engine have to run before O2 heaters are turned on? Does the car have to drive or can it idle in the driveway?
Temps have been 80-90F here lately so I'm guessing this may affect it.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Thank you, I had printed out said schematic and used it in my troubleshooting over the weekend. My apologies for the poor description. I will try again.
If I disconnect every O2 sensor (and sim) from their respective connectors, there is no continuity to ground from the #15 fuse. If I connect any one of the 4 sensors, then the #15 fuse has continuity to ground. I have physically inspected all wiring that is accessible, pulled off the fender, removed the battery and PCM to access the harness but have found nothing apparently shorting to ground.
I suspect my next best option is to put everything back together and connect only 1 sensor at a time, starting the engine and waiting for the fuse to blow. How long does the engine have to run before O2 heaters are turned on? Does the car have to drive or can it idle in the driveway?
Temps have been 80-90F here lately so I'm guessing this may affect it.
If I disconnect every O2 sensor (and sim) from their respective connectors, there is no continuity to ground from the #15 fuse. If I connect any one of the 4 sensors, then the #15 fuse has continuity to ground. I have physically inspected all wiring that is accessible, pulled off the fender, removed the battery and PCM to access the harness but have found nothing apparently shorting to ground.
I suspect my next best option is to put everything back together and connect only 1 sensor at a time, starting the engine and waiting for the fuse to blow. How long does the engine have to run before O2 heaters are turned on? Does the car have to drive or can it idle in the driveway?
Temps have been 80-90F here lately so I'm guessing this may affect it.
SO, you should be able to troubleshoot this with the KEY ON/ENGINE OFF.
Yes, plug in ONE sensor at a time and see when it blows. Be careful, those O2 sensors get HOT!
Measure the supplied voltage at the test slots on top of the fuse to chassis ground and make sure that your ignition switch is supplying the full 12 VDC/battery voltage that it is suppose to.
BC
