[hc803]

2004 SR5:
2 weeks ago closed the rear and it closed/locked but not all the way (rear cargo area light stayed on). Couldn't get it to release via button switch, so pulled/replaced the fuse in the engine bay box to the ECU-B, still nothing. Took the hatch door panel off and manually released, reset ECU-B fuse again and got it to close properly. 2 days later, wouldn't open. This time I disconnected the neg battery cable and let it sit for a few hours. Reconnected and everything was fine until yesterday. Now it won't open again.

Button switch seems to be ok (i.e., not melted), door latch mechanism appears fine (no rust, moves easily by hand).
Thinking it's the ECU-B but other than running a test voltage across it, not sure of how to test the thing. Don't really want to start throwing parts at the problem and was seeing if anyone had a suggestion.

20 years with nothing more than the normal recommended routine maintenance, so I can't complain too much!

[SocalSam]

Is the actuator trying to open, then fails, and then cycles back to locked?

[markgt531]

same thing happened to my 06 and been like that for years. i usually just roll the rear window and manually unlock it. id reset the ecu-b and works only once. Just recently my batt died, got new one and for some reason it works and its been 3days now still functions. Not sure why but ill take it. hope this helps

[Syr4RinNC]

It looks like on ebay the ECU is about $75. If thats your primary guess, I think it would be reasonable to start there. You'll know and can rule it out

[weberlukas74]

Given the signs, it's likely that the ECU-B is causing the issue. But I suggest checking a couple more things.
Have you tested the continuity of the wiring harness going to the lift gate? Broken or frayed wires might be causing the problem.
Also, maybe, check the actuator motor itself.
And btw, have you noticed any unusual sounds or sensations when operating the lift gate?

[Nunya Biznass]

I've been having similar issues with my '06 Sport recently.

One day, I closed the hatch and noticed the sound of the actuator cycle was different. It lasted slightly longer and had a slightly different pitch.

Afterward, the lift gate wouldn't open. I pulled the ECU-B fuse to reset the control module, and then it opened. The sound on closing again seemed normal and it opened as expected. But after the 2nd time closing, it again refused to open.

Pulled the fuse again, and it opened once; but after closing, it won't reopen.

So basically, I have to pull the fuse to get it to open every time now. The latch mechanism looks good (grease present, no rust) and operates smoothly. I suspect it's the control module, but like you, have no idea how to test it to verify.

[SocalSam]

Originally Posted by SocalSam

Is the actuator trying to open, then fails, and then cycles back to locked?

You never answered my question.

[Nunya Biznass]

Originally Posted by SocalSam

You never answered my question.

In my case, the answer is no. The release handle does exactly nothing. No sound, no motor activity, nothing. It behaves exactly as if the door were locked.

I presume OP's is behaving the same.

[SocalSam]

Originally Posted by Nunya Biznass

In my case, the answer is no. The release handle does exactly nothing. No sound, no motor activity, nothing. It behaves exactly as if the door were locked.

I presume OP's is behaving the same.

What condition is hatch release button?