[V6-12v] Need help with cooling problem

[Tom Christiansen]

Al,

If the fans don't run at all, it's probably bad fans or the thermo 
switch. It's located on the bottom right (passenger) side of the 
radiator. It has a fairly big (like 1-1/4" diameter) round plug on 
it. Check the ground connection on the left side subframe by the rad 
fan resistor pack as well.

If the fans will only run at high speed, it's a blown resistor pack 
(located on the left front subframe). Looks like an L-bracket with 
wire taps on it.

There are three (3) coolant temp sensors in the car:
1) Bottom, right of the radiator. Controls the rad fans.
2) In the coolant pipe on the left (drivers side) of the engine. Near 
the EGR valve. 2-pin device. This gives the ECU temperature info.
3) In the coolant pipe on the right side (passenger side) of the 
engine below/near the idle stabilizer valve. 3-pin device (new style) 
4-pin device (old style). No wiring changes are needed to change from 
a 4-pin to a 3-pin sensor. This sensor controls the temp gauge and 
overheat warning light.

Tom

At 07:13 PM 8/20/2005, you wrote:
>Today my wife's 1993 90Q tried to overheat while she was driving in 
>town. Fortunately, she pulled
>over and shut it down before any damage too place. The problem is 
>easy to spot - the radiator
>cooling fans weren't running.
>
>I checked all fuses in the fusebox, and they're all good. I have 
>both the Bentley CD and a Mitchell
>CD, and neither was much help. The only mention of a something to 
>test is the Engine Coolant Temp
>Sensor, and it's described (depending on the source) as being at the 
>rear of the engine both on the
>left side AND the right side. Swell. I can't find the darn thing.
>
>I suspect the culprit is either an engine temp sensor or the 
>three-connection relay strip located in
>the driver's side front fender, but I can't find ANY test procedures 
>for the strip, and I can't find
>the temp sensor. Not helpful.
>
>Tomorrow AM I want to download the codes as per the procedure at
>http://www.12v.org/maintenance/dtc.php . Unfortunately my MIL 
>(engine malfunction indicator light)
>is burned out, so I need to use the test light method - but although 
>the method is referred to on
>the website, I can't find a description of the method on the 
>website. Can anyone help me find it??
>(On the 200 models, I believe the test light connection point was a 
>pair of connectors in the
>driver's side footwell, but I checked and don't see any such 
>connectors on this 90Q.)
>
>So, to sum up, I'm looking for:
>1) Confirmation of where the Engine coolant Temp sensor is found.
>2) Test process for the 3-connector relay in the driver's front 
>fender. (If any)
>3) Where to connect a test light to check codes on this car.
>
>If I can't find something to try before Monday AM, it's going to the shop.
>
>BTW - curiously, when I tried to check the codes before finding the 
>MIL light was out - the cooling
>fans ran for a moment. But they stopped and didn't come on when I 
>warmed up the engine...so I'm
>still thinking it's a relay.
>
>I also spotted a small radiator leak, but that's the next project.
>
>************************************
>Al Powell
>apowell at gocougs.wsu.edu
>1958 Fiat 1200 Transformabile Spyder
>1983 Datsun 280ZX Turbo
>1993 Audi 90Q
>1991 Camaro RS Convertible
>1997 Chebby Blazer
>1999 Chebby Blazer
>************************************
>
>
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