Electrical gremlins, possibly BCM

[vetteman9368]

Truck is a 2004 Yukon SLE, 2wd, 4.8, almost as completely base truck as you could get. We got it from my mom for my 16 yr old daughter. She bought it new but it’s been mostly sitting the last year or so. Here’s what’s going on

-abs light and message on (gotta resolder the ebcm).
- dic says rear access is open when it’s not.
- HVAC controls inop (manual, fan does nothing)
- shift indicator is off, not just dim (possibly unrelated)
- power locks don’t work from drivers side switch, neither do mirrors, windows are hit or miss using drivers switch

I halve already cleaned the grounds under drivers door. My multimeter is junk so I gotta get another one to start any real testing. Any thoughts?

 

[wjburken]

Truck is a 2004 Yukon SLE, 2wd, 4.8, almost as completely base truck as you could get. We got it from my mom for my 16 yr old daughter. She bought it new but it’s been mostly sitting the last year or so. Here’s what’s going on

-abs light and message on (gotta resolder the ebcm).
- dic says rear access is open when it’s not.
- HVAC controls inop (manual, fan does nothing)
- shift indicator is off, not just dim (possibly unrelated)
- power locks don’t work from drivers side switch, neither do mirrors, windows are hit or miss using drivers switch

I halve already cleaned the grounds under drivers door. My multimeter is junk so I gotta get another one to start any real testing. Any thoughts?

Get your multi-meter replaced.

Get a good code reader and make sure you know what’s going on with the ABS.

Use your new multi-meter to check fuses and voltages.

How old is the battery? Have you had it tested?

What voltage is your alternator putting out?

 

[Doubeleive]

all typical things that individually fail on a 20+ year old vehicle
bcm failure is very rare
for the hvac -check blower motor resistor
drivers door switch -try another switch
instrucment cluster - can be rebuilt/repaired, check craigslist for local repair, lots of people do this as a side gig
rear access hatch -going to take a little more troubleshooting, could be the acuator/sensor in actuator

 

[vetteman9368]

Get your multi-meter replaced.

Get a good code reader and make sure you know what’s going on with the ABS.

Use your new multi-meter to check fuses and voltages.

How old is the battery? Have you had it tested?

What voltage is your alternator putting out?

Only codes are u1000 and u1096, but the cluster works except temp and the shift indicator.

Battery is 6 months old and just fine, alternator is putting out 14.8v

 

[vetteman9368]

all typical things that individually fail on a 20+ year old vehicle
bcm failure is very rare
for the hvac -check blower motor resistor
drivers door switch -try another switch
instrucment cluster - can be rebuilt/repaired, check craigslist for local repair, lots of people do this as a side gig
rear access hatch -going to take a little more troubleshooting, could be the acuator/sensor in actuator

The cluster I’m not worried about, I have a box full of stepper motors, more worried about the shift indicator for my daughter

 

[Doubeleive]

The cluster I’m not worried about, I have a box full of stepper motors, more worried about the shift indicator for my daughter

shift indicator is part of the cluster, the display fails and should be replaced, requires soldering
if you pop it open and look they are typically burnt and black

 

[Doubeleive]

could depend on where it is burnt, in this video he was able to just resolder the resistors, but sometimes the display it's self burns out

 

[vetteman9368]

shift indicator is part of the cluster, the display fails and should be replaced, requires soldering
if you pop it open and look they are typically burnt and black

I’m just trying to find a shift indicator

 

[Doubeleive]

I’m just trying to find a shift indicator

I posted a video above, in any case you should pull it and open it up and take a look could be a easy fix

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[vetteman9368]

Some updates this afternoon.
-rear access open message won’t go away, even with the harness unplugged from the bcm.

-installed new stepper motor for temp gauge

-shift indicator is toast (has a burned spot on the display, didn’t work even after a resolder. Anyone know who sells the display?

So far that’s all I’ve got. Thinking I may need a bcm, does it have to be programmed or will the 30 min relearn procedure work?

 

[Doubeleive]

Some updates this afternoon.
-rear access open message won’t go away, even with the harness unplugged from the bcm.

-installed new stepper motor for temp gauge

-shift indicator is toast (has a burned spot on the display, didn’t work even after a resolder. Anyone know who sells the display?

So far that’s all I’ve got. Thinking I may need a bcm, does it have to be programmed or will the 30 min relearn procedure work?

rear hatch is probably a sensor, most likely integrated in the lock actuator. could maybe be a magnetic one but they pretty much built those into the actuators after 02, highly unlikely to be the bcm
not sure where you could order a shift led, might check with any local cluster rebuilders

 

[vetteman9368]

I took the hatch apart and even unplugged both sensors, nothing changed. Even unplugging the harness from those sensors to the bcm changed nothing.