Hi guys. Please allow me to add a comment of value. I didn't reply earlier because the photo of the relay I looked up only showed one mounting bolt hole. In the drawing posted by ASEMASTER6371, they show the same electronic relay used way back to the mid '90s on Neons and minivans. If this is the style you have, there was a recall to replace the two mounting screws and the relay if it had shorted. Seems the screws would break, then the metal heat sink would lift away from the sheet metal "core support" around the radiator. We were to clean that area, install a new relay with the two new screws provided, and we were to add heat sink compound. If you aren't familiar with that, it's like a white or cream-colored sticky grease that goes between the physical contact point of the body sheet metal and the metal plate on the relay. It promotes heat transfer so the relay doesn't overheat.
This electronic relay works by switching current fully-on or fully-off at varying percentages to adjust fan speed. This isn't actually a relay at all. It is electronic circuitry that turns a beefy switching transistor on or off. The idea with any switching power supply such as this is when it's switched off there's 0 current so now power, (heat) dissipated. When it's switched on, there's a lot of current, but no voltage dropped across the relay, so again, no power dissipated. The relay should remain cool under all conditions. That's the ideal version of the story. If it were perfectly true, that heat sink wouldn't be needed.
On that subject, I know from painful experience that if that relay is hanging by the wires after the screws broke, it will get hot enough to burn your fingers, so watch out for that.
If you already had the heat sink grease in place but are having multiple relay failures, given either the age or mileage you listed, you might suspect tight bearings in one of the fan motors. With the ignition switch off, try spinning the fans by hand. Both must spin easily and take some time to coast to a stop. If one stops almost the instant you spin it and let go, that motor will draw higher-than-normal current and will lead to the relay overheating.
Sep 9, 2021 at 5:35 PM
