2018 Navigator Reserve L, 101k.
Liftgate was closed and would not open no matter how initiated - dash button, exterior liftgate button, keyfob. Would not unlatch.
Scanned it with an Autel MK808 which reported B1452:11-48 and B1453:29. I'm convinced an electronic part failed but trying to identify which one by following the procedure available in the online Navigator shop manual.

Funny thing is that, after manually releasing the liftgate, I could manually set the latch and it would electronically unlock (using dash, exterior, interior, and keyfob buttons). But close the liftgate and it would not unlatch so I could pull it open. Makes me suspicious of the latch sensor.

I need the wiring diagram with connector pinouts to proceed. I have ordered a used one but it won't be here for a week or so. Will anyone share that wiring diagram? I'm particularly interested in the RGTM connector pinouts and all the liftgate sensors - latch, pinch, etc.

Thanks for any assistance.

Lloyd

 

Your 2018 is too new and I don't have any diagram for it.

Best thing you could do mechanically to lubricate the latch mechanism. Do a manual release like before, but this time you don't close it immediately.
1) you lubricate moving parts with only dry lube like this (but do not spray the electronic parts)
2) electronically latch and unlatch it repeatedly (without closing the liftgate) and spray dry lube for the 2nd time (but no 3rd time and overspray it)
3) close it

 

That’s good maintenance advice and I’ll do that as part of this job. Because the module is reporting codes, I’m convinced there is an electronic failure so I don’t expect lubricant to solve my problem.

 

When you have to do so much to manually unlatch it you just have to lubricate while you are at it, and not to mention it can be a possible root cause of the DTCs you received due to lack of lubrication.

 

That sounds like a classic latch sensor issue if it works once manually released. I don't have the diagram handy, but try searching for "2018 Navigator Workshop Manual PDF" on some of the other Ford forums. Those huge factory manuals usually have the full wiring diagrams and pinouts you need in the body section.

 

Thanks for the reply. Can you be more specific about the "classic latch sensor issue"? I got a one month AllData subscription so I have access to the shop manual including schematics. I followed the troubleshooting procedure and the RGTM (rear gate/trunk module) was not generating the "unlatch" output, which doesn't exactly jive with it unlatching when it was open. But that got me to order a new RGTM. I also buggered up the latch motor trying to manually release it - I went in at the wrong place and ended up punching a hole in the plastic motor casing; it probably still works but I wonder how long it will last after the damage, so I ordered that as well.

Those parts were not cheap - $500 from FordPartsOnSale.com and about twice that from a local dealership. So if there is the latch sensor is separate and possibly the culprit, I would like to check first. I can return the parts I ordered if I don't use them (but once installed, they are mine).

Lloyd

 

You have Autel MK808 with bidirectional support why don't you run active test to the RGTM or even reset it?
Additionally why don't you try to find a repair shop on eBay. You know you have to program the new RGTM do you? And your Autel might not be able do it.

 

Thanks for the reply.

Apparently my version of the Autel MK808 does not have an active test outside of what it does when it reads codes. It does warn that the liftgate may open when reading codes so it must be running some active tests. I cleared codes and read them and got the B1453:29 again. ChatGPT seems to think it's the latch assembly. So I will try that when the part arrives Monday.

Lloyd