Need help badly -- Hybrid Vehicle

[german_cargo]

TL;DR

Hybrid Vehicle help

Summary: Hybrid Vehicle help

I'm having a problem with my 2008 Ford Escape Hybrid project. There is a small Motor Electronics Cooling pump that isn't working, and after a while it over heats, trips a sensor, and the computer puts the car into limp mode until it cools off. I have a Factory Service Manual for the car and followed the diagnosis steps checking voltages and grounds, and based on the steps I've followed there is a problem within the circuit within the huge wiring harness that comes off the firewall.

So that's all fine and good -- my plan is to just bypass the harness with a new wire. According to the FSM, the component is supposed to be running 100% of the time the vehicle is on, so I can wire it in really simply and there isn't even a relay I have to hit. My plan is to go from the fuse in the power distribution center straight to the pump.

Here is where I'm running into issues: When I get temporary wiring and aligator clips and connect directly to the 12 volt car battery, the pump doesn't spin. This is the 2nd pump I've bought that won't spin either installed in the vehicle with coolant in it or on a bench. Originally I thought maybe the ground was bad, but with my multimeter and a test light I confirmed that the pins on the connector for the pump are getting 12 volts.

The FSM doesn't have any instructions on how to test the motor by itself. Have I managed to buy two defective pumps in a row, or am I missing something? Is there a reason why a car battery hooked up to the pump directly wouldn't make it spin besides the pump being faulty?

 

[anorlunda]

Boy, you don't give us much information to go on. I wonder if it might be an AC motor designed to run with VFD electronics, or perhaps a BLDC motor driven by a controller Connecting it directly to 12DC might damage it.

But that's all speculation, because I don't even know what motor you're talking about.

I'm going to move the thread to automotive. Maybe better answers there.

 

[berkeman]

Summary: Hybrid Vehicle help

my plan is to just bypass the harness with a new wire

Um, have you considered taking it to a dealer to have them diagnose and fix the problem? Bypassing stuff in electric vehicles can have unintended consequences sometimes...

https://cdn.motor1.com/images/mgl/2...-electric-vehicle-for-additional-training.jpg

 

[german_cargo]

Boy, you don't give us much information to go on. I wonder if it might be an AC motor designed to run with VFD electronics, or perhaps a BLDC motor driven by a controller Connecting it directly to 12DC might damage it.

But that's all speculation, because I don't even know what motor you're talking about.

Sorry for the lack of info. I wasn't sure where to start or what's relevant. I have lots of info on the wiring of the car via the Ford Service Manual, but have found almost nothing on the pump itself. I actually considered that the motor could be AC but I can't find any real specs on the pump. The fuse for it is in the fuse box with the rest of the 12 volt car stuff like the fuel pump and HVAC and there isn't anything I can tell on the wiring diagrams that would suggest its not DC like the rest of the components that go through the fuse box. And I don't know how much this matters but when I tested the connector with my multi-meter I had it on the VDC setting and it measured 12.6 volts. Would it still read that if it was VAC? I also used an unpowered test light on the connector and it lit up -- again sorry for my ignorance, but do those only work with DC?

The motor's connector has 2 pins and I've confirmed that one is hot and reads the same exact voltage as what the 12 volt car battery reads when I measure it post to post, and the other connects to ground. I've cleaned the ground (it wasn't corroded / loose).

I've attached the most relevant wiring diagram, and here is the pump itself: https://www.amazon.com/dp/B00G8XNFPA/?tag=pfamazon01-20

 

[german_cargo]

Um, have you considered taking it to a dealer to have them diagnose and fix the problem? Bypassing stuff in electric vehicles can have unintended consequences sometimes...

Yeah, I thought of that and my intention was to run its 10 amp fuse between it and the battery. And it's not part of the high voltage traction motor / battery cell system. It's run off of the same 12 volt car battery system as the head lights and radio. Shouldn't installing a fuse and using good, weather sealed butt connectors be safe?

I had it at a hybrid vehicle repair shop a couple weeks ago and paid $300 for them to apparently replace a fuse, which obviously didn't fix it. When the pump failed again I checked the fuse and it was just as grimey as all the other fuses in there from 2008 so I'm not even sure what actually they did. I've since verified with the FSM that the fuse in question is the only fuse for the pump.

 

[sysprog]

other than for something immediately simple, It's not a fix-it-yourself assemblage -- it's very sophisticated -- I echo @berkeman's idea about avoiding unintended consequences and taking it to the dealer-- when you bought that vehicle, you bought into its maintenance exigencies -- I urge you to put the alligator clips away, bite the bullet, and, despite the expense, take it to the factory-authorized repair facility . . .

 

[sysprog]

@german_cargo -- a fuse replacement shouldn't cost $300, even if that includes the diagnostic procedure by which the fuse replacement is indicated -- and if the system still has failure evident thereafter, it seems to be that you're not getting appropriate value for your expenditure -- maybe you should avoid shops with only self-proclaimed competency regarding your vehicle, and seek a factory-certified facility.

 

[german_cargo]

I very well might have to bite the bullet and take it in, but I feel like I'm so close to figuring this out. Maybe if I can prove that the motor is broken I won't have to go bypassing stuff. There isn't anything on the circuit diagram about a voltage controller for a BLDC or VFD. Would it be built into the PCM?

I don't know if this helps but this is a little motor that runs at one speed as long as the car is on, and when it fails, you can usually tell because if you tap it with something it'll usually start working temporarily again like a starter according to a ford technician on YouTube.

Tomorrow I'm going to check what's coming out of the PCM harness, and try to determine if it's AC or DC. One of the possibilities in the Factory Service Manual is that the PCM is bad.

 

[Tom.G]

That wiring diagram you posted shows the pump labeled "M/E/COOLANT PUMP MOTOR" to be controlled by a relay by the same name, and fed with Fuse F14, 10Amp.

The usual problems are a blown fuse or a failed relay. Here are a few troubleshooting steps:

Have you tried connecting the pump directly to the battery? You may need to pay attention to correct polarity. Pin 1, BK-GN, should be Ground and pin 2, GY-YE, should be Hot.

1. check the voltage at each end of the Fuse F14, should be battery voltage.
2. connect you meter to the connector that plugs into the pump
3. check that there is voltage at the connector when you know there should be
4. Put a finger on each of relays "M/E/COOLANT PUMP MOTOR" and "HEATER PUMP RELAY"
   • Have sombody turn the ignition On and Off and see if you can detect the relays operating (you don't say if "HEATER PUMP RELAY" should be on or not)
5. The two relays are probably identical which means you could swap them to see if there is any improvement.
6. The wiring diagram shows that the two relays are connected to the "AUTOMATIC CLIMATE CONTROL SYSTEM" (the two top wires in the diagram, "A" and "B") which may also affect their operation

Please let us know of any progress, or lack thereof!

Cheers,
Tom

 

[JBA]

Summary: Hybrid Vehicle help
This is the 2nd pump I've bought that won't spin either installed in the vehicle with coolant in it or on a bench.

I am not dismissing the possibility that there may well be another issue; but, are the replacement pumps you bought OEM or aftermarket items?

Edit: I just discovered that if you Google "2008 Ford Escape Hybrid coolant pump problems" you will find a lot of information related to your pump issues. Including a 2014 Ford recall including your year model for "faulty cooling pumps".

 

[Dullard]

If you bench tested the pump (and it didn't work), your first (and likely only) problem is the pump.
-I'd repeat that bench test, verifying that I had good connections of the proper polarity.
Assuming still no joy:
-I'd then determine whether the pump is drawing any current (sparks on connect/disconnect are a good [primitive] indicator). An ammeter will also work.
-If it is drawing current, I'd check for a stuck impeller - the motor will probably heat up and open a thermal switch if it's operated with a stuck impeller for any length of time.
-If it's not drawing current (make sure that it's cooled off), the pump is NFG.