Door Ajar sensors

[jr1under]

I'm going in circles chasing an issue in my 1999 5.4. Even after a hard reset, the scanner consistently shows B1318-Battery Voltage Low and B1323-Door Ajar Warning Lamp circuit failure. The battery is new, alternator is fine, and the lamps always turn on and off as expected so I removed the three most likely sensors, driver's door and the two in the liftgate, and brought them in to test.

The driver's door and liftgate door sensors are identical and test as expected, normally closed, normal being when the door is shut and the plunger is pushed in. However, the liftgate window sensor is a different part # and tests normally open, the circuit closes when the window is up and opens when the window is shut. I don't know if this is a problem or just how it's supposed to work and I'd appreciate hearing from someone who can explain.

 

[BlackBetty]

Also, I would check the other doors as well. Remember a coworker had a similar issue; his interior lights would not cutoff until they hit that “I’ve been on way to long” limit.

I ended up finding the rear driver door switch to be bad.

 

[jr1under]

Also, I would check the other doors as well. Remember a coworker had a similar issue; his interior lights would not cutoff until they hit that “I’ve been on way to long” limit.

I ended up finding the rear driver door switch to be bad.

How did you determine it was bad? Was it obvious like the push pin was sticking or the wiring/connector damaged? So far, I've checked the driver door switch and the two in the liftgate with no indication of trouble.

Moving on to the other three doors as suggested. I know there's a good chance this is a GEM issue but that's a problem I can't fix so I'm hoping it'll turn out to be a bad switch.

 

[Hamfisted]

If you have the ForScan app and a laptop, you can select the door and tailgate PIDs and have an assistant go around the truck and open and close the doors / tailgate and watch the response in ForScan to see if everything is working properly. Circuits, switches, modules, etc ...

 

[Billme]

If you have the ForScan app and a laptop, you can select the door and tailgate PIDs and have an assistant go around the truck and open and close the doors / tailgate and watch the response in ForScan to see if everything is working properly. Circuits, switches, modules, etc ...

You just can’t replace Hamfisted

 

[jr1under]

If you have the ForScan app and a laptop, you can select the door and tailgate PIDs and have an assistant go around the truck and open and close the doors / tailgate and watch the response in ForScan to see if everything is working properly. Circuits, switches, modules, etc ...

No laptop but how about an iPad with the ForScan Lite app and a compatible scanner? Haven't used this combo enough to know if it's capable of those PIDs but I'll find out.

 

[jr1under]

The story so far...my 99 EB consistently reports a B1323-Door Ajar Warning Lamp circuit failure. Not the most urgent problem but I still want to understand what's going on. I suspect it's a GEM problem but testing that requires gaining access to the GEM which is not something I'm going to attempt for the first time. So trying to eliminate the other possibilities.

I removed and tested the six door ajar sensors and found zero signs of trouble. No corrosion, connectors full of grease, plungers not sticking - only point of interest was the liftgate window switch is NO while the rest are NC. But still the B1323.

So I spent some time learning to use FORScan Lite on an iPad, connecting via an OBDLink MX+ scanner. One of the pictures shows all the tests(PID's ?) I could find for door ajar status. The values changed as expected when the doors opened and closed.

All this involved a lot of battery disconnect/reconnect cycles. After each one, I'd take a short drive and then rescan and I noticed a pattern - the B1323 was constant but usually there was another seemingly random code like these:

B1318 Battery voltage Low
B1410 Left Front Power Window Motor circuit failure
B1325 Door ajar lamp battery short
C1726 Rear pneumatic fault
B1352 Left Front Temperature Damper Motor
---------
P0500 Vehicle Speed Sensor 'A' Circuit

They come and go and I think they're just ghosts in the machine. The P0500 would be a concern had I not been following Billme's thread on that topic. Instead, my conclusion is that the GEM is exhibiting erratic behavior as it ages, a topic some of us are familiar with. And unless it gets worse, I'm ignoring it.

 

[jr1under]

Add "B1450 Wiper select switch circuit failure" as another random code that's paired with B1323.