Cooling fan motor

[spiderron81]

I have a problem with my radiator cooling fan not operating. I have replaced the fan, I wanted to paint the holder too so I went ahead and changed it. It does not appear to be the switch, when I jump it out the fan does not turn on. The weird thing is that the three red lights on the dash are also staying lit? I am concerned that I have a ground problem and not knowing how to locate it. Any help would be appreciated.
Ron

[vandor]

81 Spider? Or?

[wizard124]

Check fuse L (16 amp). The horn runs off the same fuse so see if it honks. Always hot.

Check that the LT BLU wire leading to the fan is hot. Disconnect the 2 prong connector running from the back of the cooling fan. That lead should always be hot.

If it is hot, you can re-connect the ends so that only the hot lead is connected. Take a jumper wire and connect between the NEG end of the fan connector and chassis ground. This should make the fan work.

If the fan tests good. The fan ground is at the grounding junction at the left front engine compartment. The ground works through the switch at the bottom of the radiator.

[njoconnor]

I've already replaced the radiator bottom switch on my 72. Did the fan jumper thing and the fan works great! Does the orientation of the two leads matter? Haven't had the chance to run up the engine temp since the switch replacement, but figured I'd ask while the car was up on stands and the switch more readily accessible.

Neil

[spider2081]

It does not make any difference which wire goes on the temperature control switch terminals.

[spiderron81]

How fast should the engine heat up to over 200 when the car is idling? It seems to heat up pretty quickly. I have also replaced the water pump. I am wondering if maybe there is air in the system and I don't have circulation? I think the fan switch is on the bottom of the radiator, if it is not hot enough down there the fan wouldn't be turned on?

[azruss]

check how hot the bottom of the radiator is at temp. If its cool then you are getting no circulation. That is usually due to a faulty thermostat. You can also have air trapped in the bottom radiator hose at the stat. One cure is to drill a hole in the stat valve to allow the air to escape. As I recall, i drilled a 3/16" hole in mine. You can also install a fill tee in the upper heater hose (available from Napa for a few bucks). This is the high point of the cooling system where air will collect.