Cooling Fan Operation / Overheating Issues

The SSR in normal operation, does see some higher temperatures that most people are used to seeing. Supposedly, this is due to meeting emissions standards. It is not uncommon for the temperature to reach around 235 in normal operation. Here are things you should know about the overall cooling system and how to check for problems.

There is one fan in the OEM system, but it operates in 2 speeds. With the AC on, the low speed fan should turn on around 185, if the AC system is off, fan operates as follows – Low speed on: 226
Low speed off: 219
High speed on: 235
High speed off: 226

You should be able to force the cooling fan on low by just turning on the AC, you can also force to high speed to test things out by turning on the AC and placing the cooling system into “re circulation” mode.

It is common for many people to buy a handheld programmer for $200-$300 and program the fans to come on at an earlier temperature. I had a Superchip programmer (Diablo is another popular model) and set the high speed to come on at 200 and never saw my needle over 210 no matter what I was doing or where I was. You can also have the computer reprogrammed when you get an engine tune from an LS engine expert. They can also hard code the fans to operate at a cooler temperature when they provide engine tunes. Although this is at a higher cost and not quite as easy remove and install again at will, it does allow a little better performance than a hand held tuner.

If you cannot get the fan on but all the fuses seem to be in good condition and you have power to the fan plug, there is a high probability that there is dirt in the brush area of the fan motor. There is also a very small chance that the internal resistor failed. To test the resistor, simply remove the connector, then check for continuity on the plug, center pin to either outer pin. If there is not continuity from center to outer pins on the plug the resistor is blown internally on the fan.

Dirt is the most common problem on the OEM fan, and although people rave about aftermarket fans as being better (it is in many respects), be aware that it does happen to those as well, just not nearly as often. The aftermarket fans have a shroud and that helps immensely to direct air to the radiator coils. To clean the dirt out of the fan you could try taping the back of the fan with a stick or tapping it with a hammer with the truck engine OFF, then restart to test. If that does not work you might have to remove it and hit it again or disassemble it. The fan sits against 4 tabs on the mount. There are usually tie straps holding it in. Simply remove the tie straps, disconnect the single connector, and the fan will slide out the bottom. If you want to remove the air hose on top you can get it out that was as well. With the fan out, note the foam on the front of the motor. That foam acts like a filter and does a decent job of keeping dirt out, but it does not take much for a small particle of sand to prevent a brush from touching the stator and preventing the fan from operating. Once out, you can smack various sides and the front and back side of the fan, then reconnect to test.

You can also remove the small plate and inspect the brushes, you might have to manually remove the dirt. If you are technically inclined removing the plate and inspecting the brushes is pretty easy. I had a 2004 SSR with 10k miles that the fan failed on. When I took the dirt out and reinstalled the fan, it ran for another 70k miles before I sold it with no other problems.

If you are going to replace the fan, the OEM is quite expensive but Mike In Arizona ( has a great solution. Visit his site, for a great replacement at a cheaper cost and better quality than OEM.