Once you discover a low voltage electrical outlet unscrew the plate and locate the ground neutral and hot voltage wires. This might fix your issue.
Outdoor Low Voltage Lighting Family Handyman
Low voltage reading at light switch. What the p0851 code means. The code p0851 indicates that the voltage reading from the parkneutral switch input circuit was too low compared to the manufacturers specifications for the current driving conditions. Experts on old stuff help then the switched power goes back to the fixture but if the switch is not there no power is ever at the fixture. Tighten the screws that hold these wires in place. If the switch is off and the other measurements might be phantom voltage 20 100 volts. These relays in turn were controlled by small light switches operating at a low voltage comparable to that of a doorbell.
Inspired by industrial systems that relied on relay switches to control motors lights and other industrial equipment vintage remote control wiring systems used relays to switch a current. This code is only found in vehicles with both automatic transmissions and four wheel drive capability. You would never have any voltage at the switch it is just opening the hot. The reading was 105volts on the meter again. Btw if there is power in the ceiling. A multimeter can let you know if the range is less than 120 which is the expected voltage in a homes electric wall outlet.
Thats lower than our system voltage at about 125 but not low enough to explain the severe dim out. There is no neutral for reference and in this old thing maybe no ground. He installed the switch and measured the voltage at the ceiling box where the light would be installed. The switch leg will meausre zero hot to neutral if the switch is on. A low voltage condition such as this is typically an indication that the circuit ground wire may not be properly bonded at the panel or the ground wire may not be attached or properly spliced at a connection point within the circuit. The voltage you meter at the low beam lug as it turns out is about 11 volts.
When he measured the voltage from the source it only read 105 volts on the meter. Check the ground wire within the circuit. He installed the light turned the power on but the light did not work.
Gallery of Low Voltage Reading At Light Switch
