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Proactive PEM Maintenance

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Gary,
I think "proactive" is a term that is being used here to prevent a breakdown on 8-10+ year old PEMs. For older PEM, it is likely just a matter of time before it fails, so for example, if your plan is to own the roadster for 5+ additional years, it's probably best to PLAN to have the work done at an opportune time than to have a breakdown at an inopportune time.

By planning it, "we" can probably get a more reasonable time to do the work, rather than having a failure in 3 years out on the road somewhere, then having to work the repair into the schedule of repair work already scheduled.

It's not something I've thought about much, but probably need to start.
Mark
 
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It’s the insulation that fails, usually due to the PEM over heating, usually due to the PEM fan not working, usually due to the Fan plug not surviving the service unplugging and replugging. It seems to be more preventative to ensure the PEM fan is working and the connectors are in good shape.
 
It’s the insulation that fails, usually due to the PEM over heating, usually due to the PEM fan not working, usually due to the Fan plug not surviving the service unplugging and replugging. It seems to be more preventative to ensure the PEM fan is working and the connectors are in good shape.

I like the way you think, root cause.

Is there a guide to verifying PEM fan connectors?
Is it a latent fan failiure until it cascades?
Thank you.
 
Last edited:
I like the way you think, root cause.

Is there a guide to verifying PEM fan connectors?
Is it a latent fan failiure until it cascades?
Thank you.

Unfortunately the MOLEX connector that was chosen for the PEM & PEM FAN receptacle only have a mechanical life span of 25 connections per spec.

So every time they are mated, it breaks down a little. I've replaced mine twice as they break down after a bit. Here's what mine looked like before my last repair..

FAN Receptacle plug

PEM - Plug.jpg

Notice the corrosion/damage on plug pin #1




ON the bottom of the PEM the connection looks like this...

PEM - JACK.jpg


Some corrosion on pin #1 on the PEM jack, but not as bad as the receptacle plug.

I just replaced the fan side of the plug on the harness and used contact cleaner. Seems to so far eliminated the 1144/1146 errors.
 

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For sure, the 3.0 is the same IGBT’s and plugs. One internal board was changed for the bigger capacity pack.
But my
Unfortunately the MOLEX connector that was chosen for the PEM & PEM FAN receptacle only have a mechanical life span of 25 connections per spec.

So every time they are mated, it breaks down a little. I've replaced mine twice as they break down after a bit. Here's what mine looked like before my last repair..

FAN Receptacle plug

View attachment 430235
Notice the corrosion/damage on plug pin #1




ON the bottom of the PEM the connection looks like this...

View attachment 430236

Some corrosion on pin #1 on the PEM jack, but not as bad as the receptacle plug.

I just replaced the fan side of the plug on the harness and used contact cleaner. Seems to so far eliminated the 1144/1146 errors.

That doesn't look good at all. :) Sorry for that but thanks for sharing.

Is there an easy way to see if it was replaced on my vin?

Is that connector accessible?

Maybe I should make a dedicated post, let me know and I will.
On my long drive home from California, a few different times, I saw the over the steering wheel LCD contrast go away, partially faded mostly on the right and it was difficult to read. It only seemed to happen when it was warm out, during the day, and and driving 2+ hours. Have you seen anything like this before?
Thank you
 
On my long drive home from California, a few different times, I saw the over the steering wheel LCD contrast go away, partially faded mostly on the right and it was difficult to read. It only seemed to happen when it was warm out, during the day, and and driving 2+ hours. Have you seen anything like this before?
My LCD display gets kind of wonky when it gets hot. Bad contrast, and I lose a bunch of lines of pixels. Looks kind of like a marquee with a bunch of burned out builbs. {shrug} No idea what happens in a Lotus, but it's not worth fixing to me.
 
Unfortunately the MOLEX connector that was chosen for the PEM & PEM FAN receptacle only have a mechanical life span of 25 connections per spec.

So every time they are mated, it breaks down a little. I've replaced mine twice as they break down after a bit. Here's what mine looked like before my last repair..

FAN Receptacle plug

View attachment 430235
Notice the corrosion/damage on plug pin #1




ON the bottom of the PEM the connection looks like this...

View attachment 430236

Some corrosion on pin #1 on the PEM jack, but not as bad as the receptacle plug.

I just replaced the fan side of the plug on the harness and used contact cleaner. Seems to so far eliminated the 1144/1146 errors.


the main problem here is the fact, that those plugs are designed for a max. current of 18A, a full blowing PEM-fan can pull up to 20A.

Replacing the female plug plus cleaning the PEM-side helps for a while but if you want to improve it a bit, use gold-plated connections (available from Molex !) un the female side when replacing.
 
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the main problem here is the fact, that those plugs are designed for a max. current of 18A, a full blowing PEM-fan can pull up to 20A.

Replacing the female plug plus cleaning the PEM-side helps for a while but if you want to improve it a bit, use gold-plated connections (available from Molex !) on the female side when replacing.


Agreed on the current draw. I thought the gold plated ones just extended the mechanical from 25 to 100 or so connections, not increased the amp capacity. Next replacement, I'll use the gold plated MOLEX as you have suggested.

upload_2019-7-17_10-18-5.png
 
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I'm having the Level 2 PEM Gruber treatment done right now due to my ridiculous back up light issue in this thread:

Reverse Back Up Lights Not Working - Blown Fuse?

It was either that or paying Tesla $8000 for a remanufactured PEM that I imagined was pieced together with old parts from other PEM's. At this point I'm trusting Gruber more with the PEM than Tesla.

Look out for my wife’s Sig Green. It just got there this morning and needs the PEM repaired as well.
 
Unfortunately the MOLEX connector that was chosen for the PEM & PEM FAN receptacle only have a mechanical life span of 25 connections per spec.

So every time they are mated, it breaks down a little. I've replaced mine twice as they break down after a bit. Here's what mine looked like before my last repair..

FAN Receptacle plug

View attachment 430235
Notice the corrosion/damage on plug pin #1




ON the bottom of the PEM the connection looks like this...

View attachment 430236

Some corrosion on pin #1 on the PEM jack, but not as bad as the receptacle plug.

I just replaced the fan side of the plug on the harness and used contact cleaner. Seems to so far eliminated the 1144/1146 errors.
Yuck the 1.5 connectors seem far more robust.
 
I'm having the Level 2 PEM Gruber treatment done right now due to my ridiculous back up light issue in this thread:

Reverse Back Up Lights Not Working - Blown Fuse?

It was either that or paying Tesla $8000 for a re-manufactured PEM that I imagined was pieced together with old parts from other PEM's. At this point I'm trusting Gruber more with the PEM than Tesla.


8K for a a PEM?

I was quoted 12K just last week for a re-manufactured PEM. I pointed out to just replace the PEM fan connector was only a CIC board replacement to the SC adviser. He didnt KNOW that was even an option! And 1K is way better than 12K.

As I stated before, its getting to the point We know more than the SC's do.