_White_Background_square_1920px.png?width=256&height=96&name=FLEETWATCH%20Fleet%20Information%20Technology%20by%20S%26A%20Systems%2c%20Inc%20(06_28_2021)_White_Background_square_1920px.png)
Fleetwatch FMS · Junction Box Parts
Replacing an Old Solid State Relay with a New One
The terminals are in different places. When you replace the older white solid state relay (Gen 1) with the newer black one (Gen 2), the wires won’t go in the same positions. Note each wire’s terminal and color before you remove it, then move it to the matching terminal on the new relay.
⚠ Turn off power first. Switch off the breaker feeding the relay before touching any wiring. The output side carries AC line voltage. Only qualified personnel should do this work.
Gen 1 vs. Gen 2 Terminal Locations
The colored labels match from one relay to the other: L1 green, A1 red, A2 yellow, T1 purple.
Gen 1 (old, white): Crouzet GRD 84130101
Gen 2 (new, black): Crydom CKRD2410
| Terminal | What it is | Gen 1 (white) | Gen 2 (black) |
|---|---|---|---|
| +3/A1 | Control input (+) | Top right | Top left |
| −4/A2 | Control input (−) | Bottom right | Top right |
| 1/L1 | AC line in | Top left | Bottom left |
| 2/T1 | AC load out | Bottom left | Bottom right |
On the Gen 2 relay, the two control wires (A1, A2) are both on top and the two AC wires (L1, T1) are both on the bottom. Every wire moves to a different spot.
Steps
| 1 | Turn off power at the breaker feeding the relay. |
| 2 | Label every wire on the old relay before removing it. Mark each wire with its terminal (L1, T1, A1, A2) and note its color. Masking tape or wire markers work well. A quick phone photo helps too. |
| 3 | Remove the wires and the old relay. |
| 4 | Mount the new relay and connect each labeled wire to the terminal with the same label (L1 to 1/L1, A1 to +3/A1, and so on), using the table above. Go by the terminal labels printed on the relay, not by position. |
| 5 | Double-check the wiring, especially that A1 (+) and A2 (−) aren’t reversed, then tighten the terminal screws. |
| 6 | Restore power and test. When the relay is switched on, the small input status LED on the Gen 2 relay lights up. Confirm the device it controls turns on and off as expected. |
Ratings at a Glance
| Gen 1 (Crouzet GRD 84130101) | Gen 2 (Crydom CKRD2410) | |
|---|---|---|
| Control input | 4–32 VDC | 4.0–32 VDC |
| Output | 24–280 VAC, 12 A | 24–280 VAC, 10 A |
| Status LED | — | Yes (input status) |
Need a replacement relay or have questions? Contact Fleetwatch Support.