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Even when I took the car to the dealer to get the recalled part changed I ordered and got my fuse from Ebay today, the part will arrive on Tuesday
weights 5 ounces exactly.
Part number on the code: 3A0818180042/D081818/R0.2481
The numbers on the connecting bar seem to be laser etched.
It says:
Eaton
St. Louis, MO 63178
Assembed in Mexico

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art number on the code: 3A0818180042/D081818/R0.2481
Hey, your serial number is one off from mine with the same date code. Thanks for posting. Was thinking if it was counterfeit, would they bother with individualizing serial numbers? Wonder what the R number is? They're all slightly different. Maybe a resistance value? 0.2481 milli ohms? Wish I had a meter like professor Kelly:
 

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You are welcome, I'm glad to contribute to the knowledge base... Oh yeah, I'm a tool fan and would love to have that, but man 1200 is a little high for me, specially since I don't have an immediate periodic use for it!
 

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Hey, your serial number is one off from mine with the same date code. Thanks for posting. Was thinking if it was counterfeit, would they bother with individualizing serial numbers? Wonder what the R number is? They're all slightly different. Maybe a resistance value? 0.2481 milli ohms? Wish I had a meter like professor Kelly:
Professor Kelly is a member of the Forum, I would not be surprised to see a video related to this matter of the MSD failure, once my car hes the GM replacement I would be happy to sacrifice mine and sent it to him.
 

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weights 5 ounces exactly
Ditto. Also switched to grams on my scale and it was 143 g. An Eaton brochure had a size and weight comparison with other industrial fuses with their 300A version weighing in at 141 g.

In that same brochure, they mentioned the part number designation as EV for electrical vehicle. Think we all figured that one out. Followed by the diameter in millimeters. Then the amp rating. The following dash number is the terminal configuration.

So the Bolt had an EV30-400-AG. Electric Vehicle 30mm diameter rated at 400 amps with a terminal configuration of AG. The brochure listed only three terminal configurations of T, B, 1P; others available on customer request. So this might explain why there's only a hole and not a slot.
 

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Discussion Starter #27
The last part of my old fuse's part number was also R0.2481 and it's interesting if that is resistance in milli-ohms because the new one is R0.2429 which would indicate slightly lower resistance. I wonder if all those in the "bad batch" had a resistance of 0.2481 milli-ohms?

Mike
 

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The last part of my old fuse's part number was also R0.2481 and it's interesting if that is resistance in milli-ohms because the new one is R0.2429 which would indicate slightly lower resistance. I wonder if all those in the "bad batch" had a resistance of 0.2481 milli-ohms?

Mike
Thinking yours was R0.2482 where Freddy's was R0.2481 and mine is R0.2488. Yes, they're all slightly higher than your new fuse. Good catch. The higher the resistance, the more voltage drop, energy dissipation and higher heat. Could also be a threshold of the monitoring circuit where every thousandths of a milli-ohm matter. Reading a Cooper Busmann engineering fact sheet says these don't wear.

edit: so resistance increases with temperature. I bet the issue isn't a blown fuse. Just a batch of fuses that could trip the Bolt's monitoring circuitry and the car faults. If one could get the car cooled down and clear the faults, the car would be drivable again.
 

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Discussion Starter #29
Interesting. I'd sure like Weber to analyze the resistance on one of these fuses after it has caused the failure. As you said, it could be a heat thing. On the other hand, those fuses just have a number of metal ribs inside. If one of the ribs burns through, the resistance would go up significantly. In that case, maybe it wouldn't work if you just cooled it down because it'd still have that one burnt-through rib. Would love to know, just for my own curiosity.

Edit: by my calculations, the difference between .2429 and .2481 is a little less than 1 watt at full power (160kW) so I can't imagine the resistance alone would cause a problem. My guess is that these fuses aren't supposed to wear... but the bad batch does, and that leads to it increasing resistance over time.

Mike
 

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I bought my 2019 LT around Christmas. I have my "complimentary" service visit in about 3 weeks, presumably for a tire rotation. I called the dealer today to point out that I got a recall notice for my car, and it would be nice if they had the part and could do the recall service when I came in for my appointment. The guy told they've had 3 other of the MSDs on order for other customers for a couple weeks now. He said they'll add one for me, and I'll get a robocall when it comes in.
 

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Got mine replaced at the dealer today. Took about an hour or so. They also updated the software. I asked about an update to change the charging taper from a stepwise taper to a gradual decline curve, like the 2020 model. They said that that update wasn't ready yet but I should receive a notification when it's available. Of course, no charge for anything.
 

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Got mine replaced at the dealer today. Took about an hour or so. They also updated the software. I asked about an update to change the charging taper from a stepwise taper to a gradual decline curve, like the 2020 model. They said that that update wasn't ready yet but I should receive a notification when it's available. Of course, no charge for anything.
That update wasn't ready yet?!? So what have the other folks been getting when they complain of slow cold charging?
 

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That update wasn't ready yet?!? So what have the other folks been getting when they complain of slow cold charging?
Yeah, I was wondering about that myself. I wasn't completely convinced that it was a "not ready" issue, but what was I going to do? I wasn't going to argue and it's not critical for me, so I'll just wait and see what happens.
 

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After about a 2 week wait for the backordered part, I got my MSD and replaced it today. I just wanted to replace it to give me some peace of mind after seeing a few people who got stranded due to a bad MSD. For my 2019 built in March 2019, it already had the new part number (24294004) even though the date stamped on the part itself was Jan 5, 2019. I assume GM assigns a new part number if a batch is found to be bad and the TSB calls for replacing with a new part number so I likely did this for nothing. In any case, I'll have a spare at least and found that it was pretty easy to do so maybe this will help someone else. I know some people (even those with 2019 Bolts) have an older/different part number but mine ended up being the same. Interesting that the bar codes on the actual fuses are different though.

Mike
Thanks for the nice video and instructions. I wouldn't have thought that the 12v battery needed to be disconnected first, so thanks for the heads up, if I ever need to replace mine! Maybe I'll put a label on the MSD to that effect.
Also, there is a nice little cubby under the seat that you could wrap that old MSD in some foam or bubble wrap, and hopefully it will fit in there. Actually, it might not fit. I keep my wheel lock under there.
 

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Our Bolt was built in May 2019. It is included in the MSD recall notice.

In case anyone is considering buying a MSD and installing it themselves, here is my buying experience. May allay any fears of overly long wait times for the part to arrive.

I DID NOT want to take our Bolt to our local Chevy dealer for the recall service. Personal choice. Several factors, including trying to maximize our social isolation due to COVID.

Anyway, we live in Midland, TX. I bought my MSD online from the closest (geographically) Chevy parts warehouse (Scoggin Dickey in Lubbock, TX) :

gmwarehousedirect.com | OEM GM Parts & Accessories | GM Warehouse Direct

Timeline:

1. Ordered part online on July 20. Got email reply to my order later that day, telling me the part was on 2-3 week backorder, and asking what I wanted to do.
2. On July 21 I replied by email that I was happy to wait as long as it took - please go ahead and submit the order.
3. Got another email later that day saying "Are you sure? A Special Order may take 3-4 weeks?" I immediately emailed back "No problem. PLEASE submit the order".
4. On July 22 got email confirmation that my order was successfully entered into the system.
5. On July 30 got email shipping notice. Was shipped via FEDEX, which has to go from Lubbock, TX east to DFW, TX then back west to Midland, TX. Don't ask me why.
6. Package was delivered on Saturday morning Aug. 1. HOORAY!

So it took 11 days from time order was entered into system until it was in my hands. Not too bad.

My new MSD looks exactly like the new one in Reply #30 above. Same part number as the MSD in our car, but has the added black "dot" and blue "V" next to part number.

The green sticker on the original MSD in our car has a date code of 19-03-04. The new MSD has green sticker with date code 20-03-31. One year newer?

My cost was $99.79 plus $8.23 tax for total of $108.02 (shipping/handling was free). Cheap price for increased peace of mind.
 

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Discussion Starter #38
I had a similar experience and also ordered from gmwarehousedirect. They actually called me (imagine someone who knows how to use an actual phone in 2020) ;) and asked if I wanted them to order it. I said yes and the rest went similar to your experience. I did place an order with another popular GM parts place first (won't mention the name because I don't want to slam anyone) but their price was a few dollars cheaper... but they simply sent an email with "your order was canceled" with no option to order and wait. My order took 13 days. Similar to your timeline. My feeling is they (GM) tell people it's on backorder to discourage doing it yourself but if you can get them to place the order, it doesn't take that long.

Mike
 

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Also, there is a nice little cubby under the seat that you could wrap that old MSD in some foam or bubble wrap, and hopefully it will fit in there. Actually, it might not fit. I keep my wheel lock under there.
That is so cool to find hidden compartments! I discovered the same thing in my previous (gas) car. Now I'm wondering what other features the Bolt has that aren't mentioned in the owner's manual?
 
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