2013+ Ford Escape Forum banner

BMS connector & wipers non-functioning

5K views 19 replies 7 participants last post by  themajik1 
#1 ·
I’ve read many threads herein Pertaining to battery replacement and the ground/BMS cable & 2-pin connector. I did the induction housing method to remove the batter but since found the cowl removal method which is far easier and faster. In July I replaced the battery on our 2016 Escape SE. Unwittingly Cleaned the overly corroded BMS connector at the battery. The car started that nIshtar but not in the morning. I tinkered with the cables and it started. It worked since. In late August the wipers started coming on by themselves, intermittently.

Then this week it would not start. This site taught me about the BMS module which I replaced this week, along with the 2-pin connector taking care to splice the wires in the same orientation. Everything worked fine except the wipers in front are not functioning. Rear wiper, washer fluid all work - just not the wipers. I since learned here about the BMS reset with FORscan. So I ordered the cable but went to Brakes Plus for the BMS reset this morning.

The Brakes Plus tech relayed to me that there were several error codes he cleared when he did the reset But did not capture what they were. But the wipers still do not operate. I checked all fuses involved via DVM for 0 resistance, reseating them. I also reconnected the positive battery cable having read here installing that last assures proper BMS restart.

How can everything work fine, even the washer fluid and rear wiper on the same stalk, except the wipers if the BMS can cause errant operation?

In the meantime while awaiting my OBD/FORscan cable, I will be disassembling and checking the 2-wire BMS by jumpering it in the other orientation.
 
See less See more
#2 ·
Is there a method to test a BMS for operation?
I’m wondering if my new BMS/cable has infant mortality, not working from the start. But wouldn’t a whole host of other issues be occurring since this circuit powers a communication buss, I believe t least.
 
#3 · (Edited)
The connector orientation is correct (see photo). the old damaged connector on top, I clipped the leads in a loop on the replacement pigtail so as to show the white wire going to the correct connector pin in the photo.

I checked voltage to the leads in case I crimped the splice over insulation. I found 4.15-4.35 volts to the terminals with the brown lead being (+)

For an added twist, I started the car with the BMS connector off and, you guessed it, the wipers work! At least electrically I know the wipers function.

I know I can’t leave that off. I guess I’ll have to wait for the cable to interface a laptop and run FORscan to hopefully diagnose what’s going on.

Circuit component Electrical wiring Passive circuit component Wire Fashion accessory
 
#18 ·
I had the same issue. Battery was replaced along with the 2 pin pigtail. Because both wires on the new pigtail were green, they connected them backwards. Once changed to the correct connection, the wipers work. Why would 2 wires coming off of a ground matter? Makes no sense to me. This was a 2016 1.8L SE. The replacement pigtail was Ford replacement part as well. They need to color code the wires to make sure they don't get crossed. Not sure why they don't, the original was color coded. At least this thread helped me figure it out.
 
#4 ·
When you get FORScan operational, review any existing codes (ie. communication errors between modules). Then scan the BdyCM for realtime Bat data as noted in the attached screen capture. If the BMS is working, the Current, State of Charge and Days in Service should be non-zero.
 

Attachments

#5 ·
One more thing....the Wipers are controlled by the BdyCM also along the same LIN as the BMS. There may be a fault in the wiring harness as noted in other threads. See attached diagram. My wipers work, but the BMS does not after this operation on my '15 FE! The charging system is working by default, however. The dealer has no clue as to resolving the Code U1007 - Lost Communications with Battery Monitoring Sensor A.
 

Attachments

  • Like
Reactions: Jammer717
#6 ·
Thanks for the screen shots.
here is an unexpected twist: after verifying my spliced in 2-pin BMS pigtail was, in fact, the correct orientation, I started the car with the connector on and no wipers. Then I disconnected the 2-pin and started it, tried wipers and they worked! Of course when reconnected and started, still no-op.

im just a country doctor but to me this result eliminates the harness issue since everything does work. Unless a short is bringing down the BCM, I suppose.
 
#11 ·
for reference, these ghost problems could be caused by the 2-pin connector to the BMS on the ground cable at the battery terminal. If corroded and replaced, you take care to keep the proper wire orientation because the replacement part is not color coded (it serves many places with different wiring) Unfortunately several within these threads still had problems, as did I.

What it turns out to be, for the Standard brand of cable/BMS is that the 2-pin on the cable is reverse wired. This requires the repair to reverse wire the replacement pigtail in order to gain proper function of things. This happened to me. The photo shows how initially I properly wired the 2-pin pigtail and my windshield wipers would not work and FORscan revealed a BCM comm error. Once I reverse wired the pigtail I’m back to full function.
Circuit component Electrical wiring Passive circuit component Wire Fashion accessory


Grille Font Automotive exterior Mesh Gas
 
#13 ·
What it turns out to be, for the Standard brand of cable/BMS is that the 2-pin on the cable is reverse wired.
So it's the aftermarket BMS sensor that's the problem? It's somehow got it's output wired in reverse so you needed to reverse the wiring compared to the factory set up?
 
#15 ·
That's why I sometimes avoid and hate buying aftermarket parts. That's a big stuff up by the manufacturer.
 
  • Like
Reactions: Jammer717
Top