This page lists 3 electrical switch & relay parts for the 2021 Freightliner 108SD, across 1 part type, covering all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged). Every part shows its brand, manufacturer part number and fitment notes.
On the 2021 Freightliner 108SD, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches. Every listed part is A/C Refrigerant Pressure Switch.
The 2021 Freightliner 108SD was sold with 3 engines. All 3 parts on this page fit every engine.
Every electrical switch & relay part listed for the 2021 Freightliner 108SD comes from UAC.
Each part number listed for the 2021 Freightliner 108SD opens a page with every vehicle that part fits.
A/C Refrigerant Pressure Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| UAC Fits: all 2021 108SD engines | SW11204C | 🇺🇸 US 🇨🇦 CA | Binary Hpco/Lpco Switch | View on Amazon |
| UAC Fits: all 2021 108SD engines | SW11280C | 🇺🇸 US 🇨🇦 CA | Binary HPCO/Cooling Fan Pressure Switch | View on Amazon |
| UAC Fits: all 2021 108SD engines | SW11189C | 🇺🇸 US 🇨🇦 CA | HPCO Switch | View on Amazon |
This table covers the pressure switches on the A/C circuit. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.
3 A/C Refrigerant Pressure Switch parts for the 2021 Freightliner 108SD come from UAC. Every part fits all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged).
Part numbers include UAC SW11204C, UAC SW11280C and UAC SW11189C.
Buying Electrical Switch & Relay Parts for a 2021 Freightliner 108SD
On this vehicle, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches.
- You do not need to pick an engine: every electrical switch & relay part on this page fits all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged).
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, inspect the connector terminals behind any failed switch — heat damage there will kill the new part too.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: A/C Refrigerant Pressure Switch .
Frequently Asked Questions
How many electrical switch & relay parts fit the 2021 Freightliner 108SD?
Our catalog currently lists 3 electrical switch & relay parts for the 2021 Freightliner 108SD across 1 subcategory and 1 brand, covering all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged). Each part is matched to the engine(s) it fits.
Do electrical switch & relay parts differ between 2021 Freightliner 108SD engines?
No. On this page every electrical switch & relay part fits all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged). You do not need to pick an engine to choose the right row — use the notes for position and trim.
What are the signs of electrical switch & relay problems on a 2021 Freightliner 108SD?
Common symptoms include accessories that work intermittently, a click without action, or one function dead while its fuse tests fine. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, inspect the connector terminals behind any failed switch — heat damage there will kill the new part too.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 2021 Freightliner 108SD was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 2021 Freightliner 108SD?
Every part on this page already fits all 3 engine options (6.7L L6 DIESEL Turbocharged, 7.7L L6 DIESEL Turbocharged and 8.9L L6 DIESEL Turbocharged). Then swap a suspect relay with an identical known-good one from the fuse box before buying — it is the fastest diagnostic there is. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 Freightliner 108SD
Electrical Switch & Relay Parts for Other Freightliner 108SD Years
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