Let me save you some money. I've personally blown through roughly $3,200 over the last four years ordering the wrong damn parts. Not on fancy equipment. On Molex MX150 terminals and a pin pusher that didn't fit. That's what I'm gonna talk about today.
From the outside, ordering a connector looks simple. You look up a part number, click buy, wait for delivery. The reality is it's a minefield. People assume the lowest quote means the vendor is more efficient. What they don't see is which costs are being hidden or deferred—like the cost of you figuring out you ordered the wrong thing.
I'm the guy who handles custom cable assembly orders at a mid-sized automation shop. I've been doing this for about six years now. I maintain our team's pre-order checklist because I've personally made and documented 12 significant mistakes totaling that $3,200 in wasted budget.
The First Disaster: MX150 Terminals and The Gauge Trap
My first big mistake was in March 2022. We needed Molex MX150 terminals for a batch of 500 harnesses. Standard stuff. I looked up the part number, it said "16-20 AWG", and I ordered 2,000 pieces. Done. Right?
Wrong. The terminals arrived, and they were female terminals—but for a different wire insulation diameter than what we had. The outer jacket of our 18 AWG wire was too thick for the terminal's wire barrel. You couldn't even get the wire inside. They looked fine on the spec sheet. The result came back: 2,000 unusable terminals. $380 straight to the trash. That's when I learned: check the wire insulation diameter, not just the gauge.
What most people don't realize is that Molex MX150 terminals come in different variants for different insulation diameters, even for the same wire gauge. You'll see things like the 33472 series vs. the 33470 series—they look identical in a photo but have different sealing capabilities and wire ranges.
The Pin Pusher Problem: Not All Tools Are Created Equal
Then there was the Molex pin pusher incident in Q1 2024. We needed to depin a connector that had been wired wrong on a rush order. I bought a generic "Molex-compatible" pin pusher from an online marketplace. It was $12. Looked like the real thing. I thought, "There's a Molex pin pusher, it'll work."
It didn't.
The tip was just slightly too wide. I pushed on the terminal, and instead of releasing the locking tab, I bent the terminal's retention barb. The terminal jammed in the connector housing. We had to cut the entire connector off, re-terminate, and crimp a new housing. The mistake affected 22 items on a $1,100 order. The redo cost us about $200 in labor and materials, plus a 4-hour delay.
Lesson: A Molex pin pusher is not a generic tool. The correct tool—like the Molex 11-03-0031 or the 63819-0100—is designed for specific series. The generic $12 one? It cost me $200. Not a good trade-off.
The "Jack" Confusion and The Networks Reality
Another common screw-up? The word "jack." In the connector world, jack can mean a few different things. Is it an RJ45 jack for the networks cabling? Or is it a power jack for a device? I once had an engineer tell me to order "20 Molex jacks." I ordered the wrong ones because I assumed he meant an RJ45 style. He meant a mini-fit Jr. jack for the power supply side of a control panel. We had to reorder.
Here's something folks won't tell you: the term "jack" in a BOM is a disaster waiting to happen if you don't specify the series and application. Molex makes hundreds of different jacks across their networks (Ethernet) and power product lines. Be specific. Say "Molex Mini-Fit Jr. female terminal" instead of "jack".
This ties into a broader truth: supply chains for connector parts are global. You might be ordering from a warehouse in Chicago, but the part was molded in China. Understanding where your parts are made can save you headaches on lead times.
The "Where Are TVs Made" Supply Chain Reality
Speaking of global supply chains, let's talk about "where are TVs made" as a proxy for a larger question you should be asking: "Where are my parts made?"
People often search "where are TVs made" to understand quality or lead times. The same logic applies to Molex products. A lot of your Molex MX150 terminals might be made in a Molex factory in China, Japan, or the USA. The country of origin can affect shipping times and even the specific lot traceability. I've seen shipments from Molex's Chinese facilities take 8 weeks, while US-sourced stock is 2 days. If you're in a rush for a pin pusher or a specific terminal, knowing the manufacturing origin helps you make a smarter ordering decision.
Here's something people don't realize: the Molex global manufacturing footprint includes plants in the US, Mexico, China, Japan, and Europe. Just like you'd ask "where are TVs made" to understand the supply chain, you should ask your distributor "where is this lot shipping from?"
I once needed Molex Sabre terminals for a quick prototype. The standard distributor said 4-6 weeks. I called around, found a supplier who had them in stock from a Molex facility in the US. They arrived in 3 days. That's the power of asking the right question.
My Pre-Order Checklist (The One That Saved Us $890)
After the third rejection in Q1 2024, I created our team's pre-order checklist. Since then, we've caught 47 potential errors using it. Here it is:
- Verify the terminal series AND the wire range. A Molex MX150 terminal has specific part numbers for specific wire gauges and insulation diameters. Check both.
- Check the tool compatibility. Will your Molex pin pusher work on this connector series? Look up the tool number (like 11-03-0031) and confirm it works with your housing.
- Ask where it's coming from. Just like you'd ask "where are TVs made" to set expectations on shipping, ask your distributor for the origin and estimated lead time.
- Specify the "jack" or connector type. Don't just say "jack." Say "Molex Mini-Fit Jr. female terminal" or "RJ45 jack for networks."
- Order 5-10% extra for learning. Especially if this is the first time you're using that terminal or pin pusher. You will mess one up. That's just how it works.
I know what you're thinking: "This sounds overkill. I just need to order parts." I'd rather spend 10 minutes explaining these options than deal with mismatched expectations later. An informed customer asks better questions and makes faster decisions.
So, bottom line: stop guessing your part numbers. Use the checklist. Ask about where your parts are made. Get the right pin pusher. And for the love of all that is holy, check the insulation diameter on those Molex MX150 terminals. Your wallet will thank you.
