15A DOME fuse keeps blowing; identifying J6

are you using tech stream and the service manual for trouble shooting?

 

Any accident damage to the car that would have caused wiring harness damage? If so, that would be the first place to look.

If you are not aware of any wiring harness damage, then I think you are on the right track by trying to identify the junction connector J6 to see if you can take that apart so that you can measure resistance to ground of one downstream circuit at a time.

This is the sort of issue that seems minor but could end up with you towing the car to your local salvage yard. Good luck with your investigations and please let us know the outcome.

 

Inverter.

 

I doubt the inverter is the issue as the DOME fuse does not feed any circuit within that assembly. The inverter is powered down when the car is IG-OFF, while the DOME fuse provides power to some circuits continuously.

 

There might be a molded-in part number or manufacturer logo on the connector body, but it’s unlikely there is anything designating it as “J6.”

The Electrical Wiring Diagram (more info), in the Connector List section, shows the connector’s shape and the number and arrangement of terminals. J6 is a twelve-position connector, arranged something like this:

------- = -----
|A|A|A| | |B|B|
|C|C|C|D|D|D|B|
---------------

You can also review the System Circuit section, one system at a time, to see the colors of the wires that should be present. The terminals marked “B,” for example, all have red wires: one wire from the DOME fuse and two wires to the driver side junction block assembly: one to terminal 1A-30 (the ECUB terminal of the Body ECU) and one to terminal 1A-13. The Relay Locations section of the EWD has a Driver Side J/B Inner Circuit page, which shows that 1A-13 is connected to 1L-8, 1F-7, 1M-3, 1M-4, 1M-5, and 1O-5.

It means some of the terminals are shorted together inside the connector, as an alternative to wire splices. In the diagram above, all the terminals marked “A” are connected together, all the terminals marked “B” are connected together, and so on, but “A” is not connected to “B,” “C,” or “D.” If you have access to the complete EWD (EM03Q0U), see the illustration on page 10 for an idea of the construction.

I’m not sure it’s really so complicated: many of the systems listed in the Power Source chart for the DOME fuse are there only because of the combination meter, which receives power from the DOME fuse, among others.

Yes, but it might be better to start elsewhere, since there are really only two branches from J6 on the DOME circuit. If you’ve already confirmed that the load side of the DOME fuse is shorted to ground (i.e., it’s not an intermittent problem or an overload), you might start by disconnecting J23 (in the center console), and then J33 (above the headlining), to isolate most of the interior lamps and switches. If the fault is still present then, check interior light I18, and then proceed to other branches of the circuit.

 

The Radio and Player (connector R3, terminal 4, or connector R6, terminal 1) is one of several ECUs that receives power from the DOME circuit, among others. I don’t have enough information to say how likely it is to be the source of the trouble.

 

No, I haven't heard of that, but its great that you were able to pin the issue down to the radio assembly. If you note the part number, you can probably buy a used unit on eBay inexpensively.

 

I haven't seen it in a Prius, but I have seen other cars whose stereos consistently blew their branch fuses... until somebody removed the jammed CD they were furiously trying to eject.

 

Any updates on this?
I am about to change the Radio to see if I have a bad unit causing all my dome/smart key issues
I am thinking at J6 is my issue as well-

 

Oh I’ve had it out
I want to check for power at radio and such