Help With Fuse 31

[ScotM]

So Fuse 31 is for the OBD Port. When Searching for the cause of my parasitic Draw, I noticed that Fuse 31 is drawing 40 to 50 mA after the Jeep has been at rest - even after 2 or more Hours.. I think its supposed to be zero. But before I go any deeper, I have unplugged both my dashcam and my stop-start eliminator, so there is nothing more connected to it except a z auto extension cable.

Could one of my fellow jeepers stick a multimeter or amp hound on fuse 31 and let me know if you are getting a zero mA draw at rest. Thanks!!!

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[ScotM]

As. Usual I’m going to tag @Terrymo , @THAW

 

[THAW]

So no Tazer or Bluetooth OBD-II adapter connected? The factory SGW is connected?

 

[Terrymo]

I can check this weekend (although I only have a multimeter) if you very specifically walk me though the steps.

 

[ScotM]

So no Tazer or Bluetooth OBD-II adapter connected? The factory SGW is connected?

Correct,, no tazer or bluetooth adapter, and the factory SGW is connected, although it is connected with a z automotive extension cable, which i will check out today.

 

[ScotM]

I can check this weekend (although I only have a multimeter) if you very specifically walk me though the steps.

Thanks Terry.

for the multimeter, have the red probe plugged into the 400 mA fused port, and the black probe as usual. Then touch the probes to the exposed metal contact ports on fuse 31. I have attached pictures of the multimeter set up and the fuse. This assumes that the jeep is off , and has been sitting for about 2 hours. You can also use the 10 amp port as well and set the multimeter to amps. It assumes that the internal fuse has not been accidentally blown, which mine was and I had to replace it. You can check to make sure the fuse is working as follows. Set the multimeter to ohms, have the red probe plugged into the standard voltage/ ohm port, the place the red probe into the fused port, you should get a reading, if you get OL, the fuse is blown and needs to be replaced. Pictures attached.

fuse 31 is just below the bolt red 10 amps

 

[Terrymo]

Ok if you don’t make a discovery before then I’ll try it this weekend

 

[ScotM]

So I tore into the area around the IBD port to see if maybe there was a tracker from the dealer, and no, do it seems that fuse 31 is drawing power for some other reason. The manual I have suggests that the obd circuit also is a communication hub for the can bus system, so now I just need to understand if anyone else’s jeep is drawing power on that fuse when the Jeep is asleep .

anyone in San Diego willing to let me test their. Fuse 31 after their jeep has been asleep?

 

[THAW]

I'm thinking the F31 draw could possibly be the SGW that's being kept awake by your Lasfit switches.

 

[ScotM]

I disconnected the negative of the lasfit at the battery, but it is plugged into the lighter socket as well, but that should power down. I’ll disconnect at the power side on the battery and recheck. Thanks! I don’t have anything from the lasfit into the sgw cables.

 

[ScotM]

I'm thinking the F31 draw could possibly be the SGW that's being kept awake by your Lasfit switches.

Disconnected the positive of the lasfit and the draw dropped down to 20mA. So excellent thinking on you part. The lasfit is drawing 10-20mA at rest. I’ll bet the rest of the draw on that circuit comes from the no limitz.. I’d still love to know if an ordinary stock jeep has any draw on that fuse.

 

[WannFly]

out of curiosity, what led you down this path? Now i need to check my parasitic draw

 

[THAW]

I disconnected the negative of the lasfit at the battery, but it is plugged into the lighter socket as well, but that should power down. I’ll disconnect at the power side on the battery and recheck. Thanks! I don’t have anything from the lasfit into the sgw cables.

Good point; the 12V outlet should have power cut by the RELAY-RUN/ACCESSORY 2 circuit after a delay. It might be that the 12V outlet provides the ground when you disconnect the Lasfit ground wire at the battery, though (I glanced at the harness in the instructions, but 'm not sure exactly how it's configured).

The Lasfit locker switches connect to the CAN bus Star Connector (if you set it up that way), and if there's CAN message traffic the SGW will stay awake and draw power at F31.

 

[ScotM]

Good point; the 12V outlet should have power cut by the RELAY-RUN/ACCESSORY 2 circuit after a delay. It might be that the 12V outlet provides the ground when you disconnect the Lasfit ground wire at the battery, though (I glanced at the harness in the instructions, but 'm not sure exactly how it's configured).

The Lasfit locker switches connect to the CAN bus Star Connector (if you set it up that way), and if there's CAN message traffic the SGW will stay awake and draw power at F31.

Definitely has to be CAN bus traffic from the NoLimitz. as well. I have to drain down to about 65-70 mA now. So I think that will be tolerable.

 

[ScotM]

Good point; the 12V outlet should have power cut by the RELAY-RUN/ACCESSORY 2 circuit after a delay. It might be that the 12V outlet provides the ground when you disconnect the Lasfit ground wire at the battery, though (I glanced at the harness in the instructions, but 'm not sure exactly how it's configured).

The Lasfit locker switches connect to the CAN bus Star Connector (if you set it up that way), and if there's CAN message traffic the SGW will stay awake and draw power at F31.

I think putting the switch in for the dashcam power was my biggest cut in draw. The rest I now know where it is comng from, just nothing to do about it. thanks again for all your input.

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