This page lists 6 electrical switch & relay parts for the 2021 Freightliner 122SD, across 2 part types, covering all 3 engine options (12.8L L6 DIESEL Turbocharged, 14.9L L6 DIESEL Turbocharged and 15.6L DIESEL). Every part shows its brand, manufacturer part number and fitment notes.
The switch and relay system on the 2021 Freightliner 122SD covers the switches, relays and flashers that route power to everything the driver touches. All 6 listed parts are A/C Refrigerant Pressure Switch (3 parts) and Oil Pressure Sender / Switch (3 parts).
The 2021 Freightliner 122SD was sold with 3 engines. 3 parts fit every engine; the other 3 are engine-specific. Each part shows which engine(s) it fits.
The most listed brands for 2021 Freightliner 122SD electrical switch & relay parts are UAC (3 parts), DORMAN (2 parts) and GPD (1 part).
Each part number listed for the 2021 Freightliner 122SD opens a page with every vehicle that part fits.
A/C Refrigerant Pressure Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| UAC Fits: all 2021 122SD engines | SW11204C | 🇺🇸 US 🇨🇦 CA | Binary Hpco/Lpco Switch | View on Amazon |
| UAC Fits: all 2021 122SD engines | SW11280C | 🇺🇸 US 🇨🇦 CA | Binary HPCO/Cooling Fan Pressure Switch | View on Amazon |
| UAC Fits: all 2021 122SD 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 122SD come from UAC. Every part fits all 3 engine options (12.8L L6 DIESEL Turbocharged, 14.9L L6 DIESEL Turbocharged and 15.6L DIESEL).
This group includes UAC SW11204C, UAC SW11280C and UAC SW11189C.
Oil Pressure Sender / Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| DORMAN Fits: 12.8L L6 DIESEL Turbocharged | 9047326 | 🇺🇸 US 🇨🇦 CA | View on Amazon | |
| DORMAN Fits: 14.9L L6 DIESEL Turbocharged | 9045050 | 🇺🇸 US 🇨🇦 CA | View on Amazon | |
| GPD Fits: 14.9L L6 DIESEL Turbocharged | 1815437 | 🇺🇸 US 🇨🇦 CA | View on Amazon |
This table covers the senders and switches that report oil pressure to the gauge or lamp. Typical signs include a lamp that stays on, or a gauge that never moves. Confirm power and ground at the connector before replacing the sender or switch.
3 Oil Pressure Sender / Switch parts for the 2021 Freightliner 122SD come from 2 brands — DORMAN and GPD.
This group includes DORMAN 9047326, DORMAN 9045050 and GPD 1815437.
Buying Electrical Switch & Relay Parts for a 2021 Freightliner 122SD
On this vehicle, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches.
- Match the engine first. Some electrical switch & relay parts fit every engine; others are engine-specific. Each row shows which engine(s) it fits.
- 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 and Oil Pressure Sender / Switch .
Frequently Asked Questions
How many electrical switch & relay parts fit the 2021 Freightliner 122SD?
Our catalog currently lists 6 electrical switch & relay parts for the 2021 Freightliner 122SD across 2 subcategories and 3 brands, covering all 3 engine options (12.8L L6 DIESEL Turbocharged, 14.9L L6 DIESEL Turbocharged and 15.6L DIESEL). Each part is matched to the engine(s) it fits.
Do electrical switch & relay parts differ between 2021 Freightliner 122SD engines?
Some do. 3 parts fit every engine; the other 3 are engine-specific. Each row (and the filter at the top) shows which. If you're unsure which engine you have, check the emissions label under the hood or the 8th character of your VIN.
What are the signs of electrical switch & relay problems on a 2021 Freightliner 122SD?
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 122SD 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 122SD?
First match the engine — each row shows which engine(s) the part fits. 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 122SD
Electrical Switch & Relay Parts for Other Freightliner 122SD Years
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