Would this work on a Mercedes benz s430 airmatic compressor

is it 40 amps or less then it should

Will this relay work for a Mercedes R350

relays see amperage only, so if what you are trying to control does not draw more than the rated amperage of the relay, then yes

I just bought this relay to go with the viair high flow 150 set up. But it only has a pos and neg wire will the relay work?

Yes it should work. The purpose of a relay is to allow the use of smaller gauge wire for the pressure switch input from the pressure tank and on/off switch, however, you need to use an appropriately sized wire from your battery or another high amperage source direct to the compressor. The item shown is for 40 amp delivery and if this is the draw for your compressor, you should be looking at wire in the 8 gauge range for both positive and to chassis ground or all the way back to the battery. If the compressor draw is less, like something in the 15 or 20 amp range, you can still use this relay and use 14 gauge (for 15 amp draw) or 12 gauge (for 20 amp draw) for the main positive and negative run to the compressor. As stated above, the ancillary wiring for pressure switch, on/off switch can be much smaller wire gauge. An internet search should have wiring diagram info for high amp devices and possibly the Viair website. Be aware that I am NOT an electrician so do not blindly follow my input. Hope this helps somewhat.

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Viair 93940 40 Amp Air Compressor Relay for 12 Volt Compressor

Product ID: 427932808

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Details

Connector Type
Solder
Contact Material
Silver Nickel
Current Rating
40 Amps
Mounting Type
Chassis Mount
Brand
Viair

⚡40 Amp max current

🔌Four 1/4 inch spade connectors

🛠️Moisture-resistant mounting tab

Description

⚡ Power your air compressor like a boss—reliable, rugged, ready.

COMPACT YET MIGHTY - Lightweight design (just 22.7g) fits seamlessly into your setup without bulk.
PLUG PLAY PRECISION - Four sturdy 1/4 inch spade connectors ensure secure, hassle-free wiring.
POWER UP WITH CONFIDENCE - Handles up to 40 amps for reliable, high-demand 12V compressor setups.
TAILORED FOR PERFORMANCE - Each compressor requires its own dedicated relay—optimize your system like a pro.
BUILT TO BRAVE THE ELEMENTS - Moisture-resistant relay case with integrated mounting tab for durability in any environment.

The Viair 93940 is a 40 Amp, 12 Volt air compressor relay designed for high-performance compressor systems. Featuring four 1/4 inch spade connectors and a moisture-resistant mounting tab, it ensures secure, durable installations. Lightweight and built in the USA, this relay is essential for any professional-grade 12V compressor setup requiring dedicated relay support.

Specifications

Connector Type	Solder
Contact Material	Silver Nickel
Current Rating	40 Amps
Mounting Type	Chassis Mount
Brand	Viair
Operation Mode	Automatic
Wattage	480 Watts
Coil Voltage	12 Volts
Contact Current Rating	40 Amps
Maximum Switching Current	40 Amps
Maximum Switching Voltage	12 Volts
Minimum Switching Voltage	12 Volts (DC)
Number of Terminals	3
UPC	818114009402
Global Trade Identification Number	00818114009402
Manufacturer	Viair
Product Dimensions	15.24 x 15.24 x 13.97 cm; 22.68 g
Item model number	93940
Manufacturer Part Number	93940
OEM Part Number	93940
Colour	Black
Voltage	12 Volts
Manufacturer	Viair
Country of Origin	USA
Item Weight	22.7 g

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