Crossed electrical? Please help

[LostMNJeep]

Gents,

I've got a 2000 XJ Classic. Recently I took the dash a part to replace the AC evaporator (and then fix the rusted out floor pans), but here's what's going on now:

Power locks don't work. When I try to engage them the actuators sound like they want to work but nothing. ALSO the horn sounds and the rear wiper engages.

When I plug in my phone to the cig lighter or power outlet my gauges go dead, "no Bus" code pops up, "airbag" check engine lights come on, and the rear wiper engages.

When I try to use one of the map lights on the ceiling, it's dimmer than normal, and yes, you guessed it, the rear wiper engages.

I'm no mechanic and I'm no electrician, but I absolutely don't understand how by taking a part plastic trim from the dash and removing the center console that I have all these weird electrical issues now. I have searched and asked other forums and gotten no response. I'm tragically close to going to the stealership - which I really can't afford.

Thanks in advance!

[Carves]

at least your rear wiper works well .. :D

Might be worth checking for a pinch/short in the harness ... or maybe a ground that didnt get tightened properly ??

[LostMNJeep]

at least your rear wiper works well .. :D

Might be worth checking for a pinch/short in the harness ... or maybe a ground that didnt get tightened properly ??

Haha - yeah at least the rear window stays clean...

Not to sound like a total noob, but which harness would that be?

I'm sure I could've pulled a wire accidentally, but I'm not really sure where I should be looking exactly.

[4.3LXJ]

I think it is a ground issue too. A bad ground will cause issues like that when electricity seeks a new way to go.

[jdougn]

Might have to go back into the dash and make sure everything is reconnected solidly. Make sure any ground wires have a bright & clean connection. Did you do any recent electrical work like installing a radio or lights?

[LostMNJeep]

Might have to go back into the dash and make sure everything is reconnected solidly. Make sure any ground wires have a bright & clean connection. Did you do any recent electrical work like installing a radio or lights?

I've done no electrical work, and the dash is still taken apart. I've had to take my time with this repair (little cash and only time on the weekends). Hired a guy to weld in a new floor on the passenger front and rear. Still haven't replaced the AC evaporator... I decided to tackle the rust issue first - so when I discovered the electrical issue I figured I should get that resolved before fixing the AC since I'm guessing I don't need the AC for the next 9 months.

One outside thought I had was that I did drive a couple of miles with no instrument gauges - when I discovered the rusted out floor I decided to quickly throw in the driver seat and head over to the local body shop before he closed - the first thing he said was that he was surprised that the Jeep drove without the gauges plugged in... Any chance that caused a short?

[4.3LXJ]

That would affect the signals for sure. Might want to plug it in just to see what happens

[LostMNJeep]

That would affect the signals for sure. Might want to plug it in just to see what happens

Yeah, everything is plugged in and has been for a few weeks. I only drove a couple miles with the instrument cluster out.

The gauges go dead (tach, sped) when I plug in my cell phone - and return to normal when I unplug it.

I'll get to working on checking loose ground wires...

[oderdene]

check undercarpet wires going to backside. If you have rusted passenger side floor there maybe issue, short or grounded etc. check wires one by one, sometimes they look normal from outside, but little extra force, pressure makes problem

[LostMNJeep]

Ok, so I found this schematic. Looks like the horn, cigar lighter and rear defroster (also not functioning) have their own relays. I'll see what I can find for grounds coming from the junction box since they seem tied together in some weird way. If I can't find anything I might run over to the parts store to see about new relays.

[LostMNJeep]

Went to the parts store.

All the relays check out.

Checked for trouble codes... Got P1698 and P1694 - looks like ECM or wiring to ECM issues.

[jdougn]

Was the battery completely disconnected from the vehicle when the welding was done? Talking to the guys at the local jeep shop, it's possible for welding to really mess up the electrical system if the battery has the terminals connected.

[LostMNJeep]

I would like to think my welder unplugged the battery - but I'm not sure - I'll have to give him a call.

Either way, the weird symptoms started before I had the floor welded in, and I haven't had any new symptoms since.

[Carves]

Went to the parts store.

All the relays check out.

Checked for trouble codes... Got P1698 and P1694 - looks like ECM or wiring to ECM issues.


Those codes may not be relevant to your current situation ( pun intended :D ) ...

.... but rather - they are stored in the PCM memory - from when everything was disconnected.

P1694 Fault In Companion Module No CCD/J1850 messages received from the powertrain control module-Aisin transmission.
P1694 (M) No CCD Messages received from ECM Bus communication failure to PCM.

P1698 No CCD/J1850 Message From TCM No CCD/J1850 messages received from the electronic transmission control module (EATX) or the Aisin
transmission controller.
P1698 No CCD Messages received from PCM Bus communication failure to PCM. A "Companion DTC" was set in both the ECM and PCM.


Have you been right back through all the harness connections yet ?? ... I'm still thinking you have a ground / connection issue.

This a 97+ Harness ... but should be similiar. G prefixes are ground points.

http://i1143.photobucket.com/albums/n629/carves-oz/Vehicle%20Bits/Electrical/DashWiringHarness.jpg

[junglejuice]

Most often automotive electrical issues are caused by ineffective grounds....

[LostMNJeep]

@Carves - thanks for posting the grounds schematic - I've been trying to find a comprehensive list of grounds to check. I did go through and re-seat other grounds I found (under the hood, under the seats, etc) but it seems likely that when I started taking the dash apart I pulled something loose and should focus my attention there. I'll get going on the ground work today and update tonight if I come up with anything. Luckily I have the day off tomorrow too to dink around with this frustrating ordeal.

[LostMNJeep]

UPDATE and QUESTION:
So today I gave up on finding the CCD lines/grounds so I replaced some bolts that kept the dash to the frame/firewall (4 bolts and 2 nuts)... For the past 4 weeks I've just had the dash hung up on the frame studs and 2 bolts below next to the shifter.

The reason I bring this up is that now all the electrical problems are fixed! Is it at all possible that those bolts acted as ground somehow?

Yes, I'm a noob, but thought I knew how to fix SOME things.

[4.3LXJ]

Yup, sounds like you reestablished the ground

[Carves]

Good that its all sorted ... :thumbsup:

and yep ... if the ground points are on any framework ... that framework needs to be secure to the veh body.

[LostMNJeep]

Thanks again to everyone that chimed in to help - I'm not surprised that no one thought to ask about the mounting bolts to the dash to the frame - I mean, who would be stupid enough to drive around without their dash bolted down? :rolleye0012: