Suns_PSD

I purchased my car with aftermarket seats and I have spent a lot of energy and time trying to get back to being comfortable like it was stock. So my seats (now OEM 2012+ on '08 bases) and the wiring have been out several times.

Recently I started popping lumbar/ seat heater fuses instantly after my most recent seat removal. I started unplugging things from the seat and replacing the fuse to see if I can narrow down a bad control or component. Eventually I had every single thing unplugged and the wiring harness out of the seat entirely. Yet the moment I plug in this tan plug that is on the wiring harness ( I don't even understand why there's a plug that's totally on the same harness, why not just hard wire it?) it instantly pops the heater lumbar fuse. Keep in mind at this point I have the seat completely removed and I'm just holding the wiring harness with no devices plugged into it

Any advice? Should I just replace this entire wiring harness?

thanks.

Suns_PSD

Another photo from further back.

acheman8

Get a wiring diagram (try BBB Industries) and see what circuits are fed from the fuse. You should easily be able to narrow it down to a specific component or a bad wire. If i had to guess, I'd say you probably have a wire that's had the insulation compromised and is shorting to ground. No need whatsoever to replace the entire harness.

S.C. vette

Suns_PSD

Ummm, I might need help with that guys. Not sure where to even began.

acheman8

So the connector you are holding is the connector between the lumbar support switch and the control module that controls the actual pumps that inflate and deflate the supports (lumbar and bolster) in the seat. The reason there is a connector versus hardwired is so you can individually replace the components. You have either a short in the wiring or else the switch is bad or one of the pumps is bad and shorted. The only way to really isolate it is to determine which specific wire in the connector is causing the fuse to blow. You need a wiring diagram and a connector pin-out. Some simple electrical checks can determine where the fault is.

Suns_PSD

Sorry but I need wiring for dummies!

1) Since everything is unplugged, the switches and all, then the short can't be in those items. Right?
2) So this connector only has 5 wires that actually connect to each other. The other spaces are blanks. So I assume I can track it down to one of those 5 wires which narrows it down to only 5 circuits. Correct? H
3) However since it only blows once I connect the other end (the non powered side) doesn't that mean the short must be in that short region further down? Since I don't have any switches or devices plugged in I assume it's not completing a circuit that is showing a fault somewhere else on the car?

PS. This car is a low mileage garage queen that looks and operates better than new. I feel the short 100% has to be in the seat area. Keep in mind that it blew when I had reinstalled a seat after re-covering it. I did not have this problem before.

Thanks

acheman8

1) correct; if unplugged, you have eliminated them as the problem
2) correct
3) that is also correct. There is a short to ground between that connector and the end device in one of those 5 circuits

ps -- where in Texas are you located? I'm in the Houston area. If you are anywhere close by, I'm willing to meet up and we can muddle thru it together.

Suns_PSD

I would take you up on that offer in a hot second if I could get away for a day, but that's not really possible for me. However, near Thanksgiving that may very well change if you are available as I'm always in NW Houston for the Holidays.

Still not exactly certain how to proceed with a proper diagnosis with where I'm at currently. Run an external wire for each of those 5 circuits to where ever they are going and see if the fuse lives? That would be challenging with my knowledge level of electronics.

Cockroach

Seems to me the short is in the seat itself, you stated no issue until you recovered the seat. Possibly you put a hook/staple thru a wire? I'd go back and remove the seat cushion.

acheman8

I'm in Spring so a meet up is definitely feasible...

After thinking about it a bit more, I think since the fuse blows as soon as you plug the connectors together, it seems like you have a short from one of the power feeds to ground. You say you have the harness completely disconnected, but obviously there is some device still connected on the harness. In other words, you couldn't take the harness into your living room, plug the connector together and blow the fuse. The harness is not COMPLETELY disconnected. So - what device is still connected to the harness? I suspect it is the seat lumbar control module. Without knowing where that module lives, it's hard to say, but I can't think what else it could be.

Since the fuse does NOT blow while the connectors are unplugged, that tells me that the power feed from the battery to the wiring harness is OK. As soon as you plug the connectors together, the fuse blows. That tells me that there is a fault downstream of that connector -- either in the wiring to the module or in the module itself. The power feed for the module is the red/white wire on pin K of the connector. If you unplug the harness, measure the resistance between that pin and ground. If is zero or very low, there a direct short to ground somewhere on that power circuit. You just need to trace the wire as best as you can and inspect for broken or frayed insulation. If the wire looks good all the way to the control module, you possibly have a bad control module,

I hope that makes sense. Without seeing the physical harness and being able to trace the wiring, it's difficult to know 100% what the problem could be.

Suns_PSD

Hopefully we'll figure it out before the Holidays!

The wiring harness is plugged in to the large purple plug on the floor in my car. This is the power source for the harness. The seat heater module, air bag sensor, heaters, and all other seat controls are all disconnected.

Tbusa

Did u find the fix or are items listed above still disconnected?