Bad Instrument Cluster or…?

[007Stallion]

My 2007 Mustang GT…I somehow broke it

Took an extra few days off work for the 4th of July weekend so I could work on my Mustang putting in leather door panels and a leather dash pad. On day one I disconnected the negative battery cable since I was going to be working with the doors open for several days. Day 2 I took out the entire dash to install the dash pad and reinstalled on day 3. Connected everything back up and put the interior back together. Negative battery terminal was disconnected entire time.

Today, I started up the car and noticed the following:

Instrument Cluster message center reads: low oil pressure, low brake fluid, low fuel, DTE data err,

Also the TC light is illuminated, brake light on, CEL is on (sometimes); fuel & oil pressure gauges at 0. The turn signals, hazards, high beams, horn, and fog lights do not work. The parking, taillights, and low beams are staying on with the switch off, car off.

I really don’t know what else to do or check. I checked fuses in the passenger compartment and under the hood. I disconnected the positive battery cable and left both off for ~45 minutes.

Prior to this I had zero dash lights or issues (except the TPMS warning because…who cares?) Been working around cars for over 20 years, so not my first rodeo. Everything under the dash was taken apart very carefully, but I managed to screw up something!

Any thoughts as to what is going on? Appreciate any input you have.

 

[Juice]

You have a connector or multiple connectors you missed or not fully seated.

The lights staying one is a built in safety feature, so you have headlights if your switch takes a crap.

 

[007Stallion]

Thanks Juice, didn’t know about the lights staying on. I did go back and double check all the connections, but didn’t see any that were not reconnected/seated fully.

I read something on here about the IC making a “noise” when it is plugged back in. I don’t recall hearing anything, but at the time I wasn’t listening for it.

 

[DieHarder]

By chance did you remove or fail to reconnect any grounds behind the dash? There are at least 3 or 4 I believe. Some of the problems described are symptoms that would point to a loss of ground.

 

[007Stallion]

DieHarder,

Good question and I’ll check for a loose ground when I get home at the end of the week. I don’t recall having to remove any grounds when I took the dash out. I’m also going to go back a third time through all of my connections and make sure they are fully seated per Juice’s recommendation.

I forgot to mention in my first post that my scan tool brought up multiple errors codes, but the 2 that caught my eye were U1900-20 and U1900-60 which are both CAN bus failures. The U1900-60 was paired with B1342-20 under the IC group; this along with the failures I was seeing is what made me think that somehow the IC had failed.

I’m trying to make a list of everything to check when I get home.

 

[86GT351]

Have you scanned the car to see if there are any troubkle codes? Even if you donot have a Check Engine Light

 

[007Stallion]

I did scan the the car looking for trouble codes:



This is what got me thinking that perhaps the IC had failed some how after reading on forums that Ford had issues with some of these flaking out.

Now my initial thought is that all of these codes are most likely the result of something singular—mainly a faulty CAN bus communication.

I checked all the fuses for SJB under the hood and checked related fuses for the IC at the SJB.

Having to leave for work soon, I gave up when the parking lights/headlight stayed on after turning off the switch and shutting the car off. I had to disconnect the battery.

 

[86GT351]

Crazy thought. Have the battery and Alternator professionally tested.

 

[Juice]

I would fix the lights first. Dont worry about codes yet.
SJB controls lights, light switch tells sjb what driver selected. The cluster has nothing to do with the lights. Fix the open circuit between headlight switch and sjb.

 

[007Stallion]

Crazy thought. Have the battery and Alternator professionally tested.

I did think about low battery voltage and wanted to rule out that possibility; my SCT X4 was reporting 14.4x v at idle. I’ve haven’t had any issues out of either one prior.

I would fix the lights first. Dont worry about codes yet.
SJB controls lights, light switch tells sjb what driver selected. The cluster has nothing to do with the lights. Fix the open circuit between headlight switch and sjb.

I’m definitely going back over each and every connection as well as looking for any grounds that may have come loose. I’m not concerned about the codes, I only ran my scanner to see if it brought up CAN bus comms failures as that is what I was suspicious of.

Appreciate everyone’s input, now I just wait until I’m done with this thing called work to get back and go through everything again. I’ll report back what I find.

 

[86GT351]

For the SJB there are a few things to look at. You might not have done anythoing wrong with your repair. The SJB is a sealed secondary Fuse and Relay Panel. It is behind the passenger side kick panel plastic. Remove the plastic and unbolt the SJB and look carefully for a trail of water. Even the smallest amount of water can cause issues with the SJB. They are becoming hard to find. If there is water it could be coming from a few areas. One is the body seam under the dash area. Again you should be able to see a trace of water. Or it might be coming from the underhood drains for the cowl. Specifically the passenger side one. If it gets clogged when the cowl area gets wet the water cant properly drain. Instead it goes into thr cabin air filter area which is under the cowl behind the battery. At that point you would just remove the rubber drains. Simply grab with a pliers and pull. They come right out. Water will then drain externaly. Next step would be to replace the Cabin Air FIlter for cleaner airt in the cabin.

 

[007Stallion]

Appreciate it 86351GT. I’ll take a look for any water intrusion/corrosion. Also figured I’d look for any bent/misaligned pins in the connectors at the passenger kick panel.

The cowl drains have been taken care of; a few months after I bought the car (2021) my wife took it to work and thought she would do something nice and get it washed for me.

She went through the car wash and the entire passenger floor board got drenched. She was horrified (because this was my first project car—my baby) but called and told me about it after cleaning it up. When I got home, I pulled the rubber drains from both sides figuring that would help keep any future deluges at bay.

 

[86GT351]

It is a very common issue causing corossion

 

[007Stallion]

Well…I have egg on my face now. My son decided to go rechecking over all of the connections. He found one connector going into the SJB that wasn’t fully seated. The locking lever was locked in, but the connector wasn’t fully inserted.

Once fully seated, everything resolved itself.

The offending connector:


I had double checked these and didn’t find this. I really appreciate everyone’s input trying to figure this out with me.

 

[whitmanink]

Well…I have egg on my face now. My son decided to go rechecking over all of the connections. He found one connector going into the SJB that wasn’t fully seated. The locking lever was locked in, but the connector wasn’t fully inserted.

Once fully seated, everything resolved itself.

The offending connector:
View attachment 108526

I had double checked these and didn’t find this. I really appreciate everyone’s input trying to figure this out with me.

and just like that , a sigh of relief ,
it was just good ole human error , ..
i love when its a simple fix like this,,,
ive done this myself , with an 02 sensor and my maf sensor,, lol ,,
but once i seen what i did wrong, the knot goes away from my belly, and i laugh and say ,, "it was you all along ya big dummy"

 

[86GT351]

That is good news