Turn the factory dimmer knob all the way down until the dash lights have just turned off, or are at the lowest light setting. Next use a digital multimeter to measure the voltage on a dimmer circuit, then select the closest dimmer value in the available gauge: 1.7V, 3.8V or 8.0V.
R37105

*The first number in the EV² mechanical gauge part number indicates the dimmer voltage for minimum light output:
R1xxxx = 1.7V
R3xxxx = 3.8V
R8xxxx = 8.0V" The second number can be found by searching the "FACTORY MATCH EV² STYLE" Column for a desired style without an asterisk, then using the same 2nd digit. In the example above it is the R17000 series "The last 3 digits designate the pressure range and type as follows:
Rxx101 - Oil Pressure 100 psi
Rxx104 - Fuel Pressure 30 psi
Rxx105 - Fuel Pressure 40 psi
Rxx106 - Fuel Pressure 60 psi
Rxx109 - Fuel Pressure 100 psi
Rxx113 - Turbo Boost 30 psi
Rxx123 - Turbo Boost 60 psi
Rxx143 - Turbo Boost 100 psi
Rxx153 - Turbo Boost 40 psi
Rxx170 - Vac/Boost 30 in-Hg/30 psi
Rxx175 - Vacuum 0-30 in-Hg
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MODEL YEAR MECHANICAL EV² VOLTAGE NEEDED "FACTORY MATCH EV² STYLE
* = not available in Mechanical EV²"

DODGE
RAM 89-93 8V R12000
RAM 94-97 (EARLY 2ND GEN) 8V R12000
RAM 98-02 (2ND GEN) 8V R17000
RAM 08-09 (3RD GEN EXCEPT '09 1500) 3.8V R14000/R19000
RAM 09-13 (RAM 1500) 1.7V R30000*
RAM 10-13 (2500&3500 (EARLY 4TH GEN) 1.7V R30000*
RAM 10-13 LARAMIE LONGHORN 1.7V R38000*
RAM 14 & NEWER (LATE 4TH GEN) 1.7V R42000*
RAM 14 & NEWER LARAMIE LONGHORN 1.7V R39000*

FORD
F150 92-96 (OBS) 8V R16000
F250-550 92-97 8V R16000
F250-550 99-07 (SUPER DUTY) 8V OR 1.7V R17000
F250-550 11 & NEWER 1.7V R34000*
F250-550 11 & NEWER 1.7V R35000*
F250-550 11 & NEWER 1.7V R36000*

CHEVY/GM
CHEVY/GM 01-'06 3.8V R12000
CHEVY/GM 07-'13 (W/ LTZ TRIM PKG) 3.8V R18000*
CHEVY/GM 07-'13 (W/O LTZ TRIM PKG) 3.8V R18000*

NISSAN TITAN XD '16 & NEWER N/A R42000*

VW
JETTA 99.5-03 1.7V R32000*
JETTA 04 & NEWER 1.7V CONTACT FACTORY