Radiator fan not working.

Mark_vaughn · Post by **Mark_vaughn** » Mon Jul 24, 2006 10:59 pm

I have a little problem with my radiator fan. It hasnt run cense right after I got it home the first day. The previous owner had setup a override switch that linked the relay, so it could be turned on manually. This quit working, so I started looking and I replaced the sensor in the bottom of the radiator, that didnt work. So I replaced the relay. Still nothing.

Does the fan turn on about the same time as the thermostat opens up?

Any ideas of where to check next?

How do I test the relay? (IAP said it didn't have a relay... am I wrong?)

I will become best friends with my multimeter over the next several weeks it looks like.

alex · Post by **alex** » Mon Jul 24, 2006 11:10 pm

Hi all,

I am having a similar problem, and my father has suggested I look to see if I have a blown fuse first, as it would be so easy to correct. Does anyone have an opinion on the likelihood that that's the case? Also, anyone know which fuse it runs off of? Is there anything else that runs of that fuse that might give me an idea if it's blown? Finally, what ype of fuse do I need to buy?

Thanks.

So Cal Mark · Post by **So Cal Mark** » Mon Jul 24, 2006 11:31 pm

the easiest 1st step in fan diagnosis is to just bridge the two wires at the temp sensor in the radiator. The fan should run. If not, you'll have to check for power and ground. It varies abit on different year cars, but corroded fuse connections are common. The fuse may not be blown, but it may be loose and/or corroded on the ends.
A good fix is to remove each fuse, and clean the terminals with a small wire brush. Coat the terminals with dielectric grease and squeaze the terminals so that the fuse fits tightly.

Mark_vaughn · Post by **Mark_vaughn** » Tue Jul 25, 2006 2:37 pm

This may be a silly question.

Is dilectric grease an insulator or not? Should I be careful an make sure there is a connection before I apply the grease?

Also, my second fuse from the right (position 2 I think) has a short in it I found after burning several fuses. I think this is the wiper fuse, is that correct?

yap123 · Post by **yap123** » Thu Jul 27, 2006 3:32 pm

"the easiest 1st step in fan diagnosis is to just bridge the two wires at the temp sensor in the radiator. The fan should run. "

Mark,

Where is the temp sensor in the radiator? Is it on the bottom near the corner opposite end of where the hose is connected?

How do I bridge the two wires?

Thanks,
Clint

NW75spider · Post by **NW75spider** » Thu Jul 27, 2006 5:06 pm

You are correct about the location. I just did this yesterday, so hopefully I can help.

To bridge the connectors you need a short length of wire (three inches or so). Strip both ends and then slide an end into each of the connectors (same end as the original wire connects). So, when both connectors are plugged into the temp sensor, you should have a 'U' shaped wire looping between the rear of each connector.

Now that I read that, it seems clear as mud.

Mark_vaughn · Post by **Mark_vaughn** » Thu Jul 27, 2006 5:07 pm

I think that is where the problem was on my car. I changed the temp sensor (bottom drivers side of radiator). But the wires were not making a good contact with the connectors.
To test I cut the head off a finnish nail and shoved one end of each wire onto the nail. Worked perfectly with the ignition on.
So I cleaned the connections and plugged the wires back in then it worked.

For the record, I also changed the relay as well. I don't know which, if any, of these parts was the culprit. But in hindsight I should have tested the fan and cleaned the connections first. May have saved me some $$.

One other note. My car has to show almost 100 C on the dash before the fan kicks on. Then it runs it back down to about 90. I think the gauge may be a little off or is this normal?

So Cal Mark · Post by **So Cal Mark** » Thu Jul 27, 2006 5:22 pm

the fan should come on at 195F on the guage, which is about when the needle points to the 0 in 190

dielectric grease will allow current to pass, but it keeps corrosion away

good stuff to use on every electrical connection on a Spider, especially the fuse box and lamp sockets

TVST*R · Post by **TVST*R** » Thu Jul 27, 2006 10:51 pm

My fan stopped working and I over heated with coolant blowing through
my reserve cap today...I found the fan connection had not been crimped proper and
fixed it on the spot...
Always carry tools...You never know.

I may have Mark add a switch that triggers the Fan early at 78C (at
least I heard those are avail).
T

So Cal Mark · Post by **So Cal Mark** » Thu Jul 27, 2006 11:21 pm

SPAL is advertising a programmable fan controller, it can be set for any temp you wish. But with the thermostats not opening until 190, it might be ineffective

alex · Post by **alex** » Fri Jul 28, 2006 1:26 pm

One more thing before i test my fan. Do I need a certain gauge wire to bridge the fan switch, or will anything do? (I've never had to do any electrical work before!)

Alex

NW75spider · Post by **NW75spider** » Fri Jul 28, 2006 2:31 pm

You should use approx the same gauge as the existing wires.

yap123 · Post by **yap123** » Mon Jul 31, 2006 11:08 pm

Howdy,

I bridged the connector and the fan went on immediately.

I checked all the fuses and they look clean and corrosion-free.

What's the next step to check why my fan isn't turning on when my temp passes 195 degrees?

Thanks,
Clint

So Cal Mark · Post by **So Cal Mark** » Tue Aug 01, 2006 12:29 am

if the fan came on with the sensor bridged, then the problem is either a faulty sensor or connections, or a thermostat that isn't allowing hot water to the radiator. The next step is to run the car until it gets to operating temp and feel the bottom of the radiator. If it's not hot, then the thermostat isn't opening. The t-stat could be faulty or there could be air in the system. Have you had to add coolant to the cooling system? If so, there's probably air trapped at the t-stat

Mark_vaughn · Post by **Mark_vaughn** » Tue Aug 01, 2006 11:53 am

Mine is still giving me fits at the connection to the temp sensor. I am going to get new connectors and put on it.

When it gets hot, sometimes the fan doesnt start until I get out and wiggle the connection. Got to love that, expecially at a long stop light with the temp rising!!!