Bradford White 239-49817-00 Harness

The Bradford White 239-49817-00 Simulated Resistive Device Harness is a short factory harness that gives the water heater’s gas control a fixed simulated resistive device to read as part of its self-checks. Bradford White lists it for the through-the-wall gas water heaters M1TW40S(BN, CX), M1TW50S(BN, CX), M2TW50T(BN, CX) and M2TW65T(BN, CX).

Bradford White’s service manual for these TW series heaters (manual 45960A) spells out the check. The control tests the device before it allows outputs to energize, and the reading must fall between 25,000 ohms and 45,000 ohms. If the harness is out of range, the diagnostic LED flashes seven flashes with a three-second pause, the code the manual lists as the simulated resistive device harness out of specification, and a related specification-check code shows as eight-one flash. The harness is a molded lead with a black heat-shrink sleeve over one end and a white multi-pin plug-in connector on the other.

When a TW heater throws that seven-flash code, start with the connector: unplug it, check for a loose or corroded terminal, and reseat it firmly. If the code returns, measure the harness resistance with a meter with the power off and the harness unplugged; a reading outside the 25,000 to 45,000 ohm window means the harness itself has failed and should be replaced rather than bypassed.

Key Benefits

• Matches the Control’s Spec: Built to read inside the 25,000 to 45,000 ohm window the gas control checks for, so the self-test passes the way the factory intended.
• Clears the Seven-Flash Code: Replaces the failed component behind the simulated resistive device harness out of specification fault instead of leaving you chasing the gas valve.
• Plug-In Install: The molded white connector plugs straight in — no splicing, crimping or field-built resistor networks.
• Genuine OEM Harness: A Bradford White factory part for the M1TW and M2TW through-the-wall platform, not a generic resistor.

Common Questions

• What does this harness do? It supplies the fixed resistance the gas control reads as its simulated resistive device. The control checks that reading before allowing outputs, which is why a bad harness can keep a heater from firing.
• Which heaters use it? The through-the-wall gas models M1TW40S, M1TW50S, M2TW50T and M2TW65T (BN, CX). Confirm the model on the rating plate.
• How do I know it is the problem? A diagnostic LED code of seven flashes, three-second pause points to this harness being out of specification, and a resistance reading outside 25,000 to 45,000 ohms confirms it.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.