[raider82]

My father owns a 1997 Mercury Grand Marquis and he's been having a cooling problem. I figured this would be as good a place as any to find help, seeing as how the engines seem to be fairly similar to the 4.6 L powerplants in our cars. The Marquis has two cooling fans, an engine driven and an electric fan. The electric fan is not working for some reason.

We (dad and I) figured it stopped working soon after the "fantastic plastic" intake manifold had to be replaced. That was about a year ago. We have not had a major problem with overheating as we have been using the car for mainly short distance driving around town. Lately, though, we've been using the car for more prolonged driving, and the temperature gauge has been moving higher than it had ever been as far as we can remember. Two weeks ago we did some basic tests to try to weed out some causes and home in on likely culprits.

The fan itself still worked when we ran some wire straight from the battery to the power connector. We checked the fuse panels and found that the fuses and relays were still functional. We don't own a code reader and haven't rented one yet. Can anyone give some insight as to what might be wrong?

 

[Stinkfist04]

when you say you haven't rented a code reader..are you implying the check engine light is on? You've tested the fan, it works. Is the connector/wiring to the fan in good shape? On the Intake is two temp sensors. One for the gauge and one for the ecc. Are the connectors and wiring on those good? If the fan works but wont turn on then the ecc isn't sending the power to the fan to turn on.

 

[raider82]

Yes, the check engine light comes on, but we think it is on for another little annoyance that we already know about. We know where the temp gauge sender is and have confirmed that it works. We do not know were the EEC sender is but are pretty sure that is the problem. Dad and I have tried as best we can to physically trace the wiring involved with the fan. The wiring looks to be in fairly good shape, with no nicks or splices anywhere visible. The connectors appear to be in good shape as well. Can't find that other sender, though.

 

[dDUBb]

How many miles on the car ?? I had some fan problems a while back. Turned out the fan motor was on its way out. If you hit it, it would start running. After a while it just wouldnt come on at all without giving it a bump. If you turn on the AC the fan should kick on right away.

- Dan

 

[raider82]

Just to clear up any confusion, it's the electric radiator fan that isn't working. The original engine has about 156K on it, and has been reasonably well maintained. We figure what happened was a mechanic forgot to reattach something or other when the plastic intake mainifold was replaced.

Now we did have a problem with the blower motor in the '89 or '90 Chevy station wagon that required a little prodding to get working, but that heap is since gone.

The air conditioning still works and puts out cold air

 

[Stinkfist04]

The coolant crossover on the intake manifold; there is a temp sender by the coolant neck and a temp sender on the other side of the coolant crossover on the otherside of the alternator. One is green the other is grey. I believe the grey sensor is the ECC sender and the green sensor is the temp gauge sender. If you found one the other one should be about 7in away from it, both right on top of the coolant crossover.

 

[raider82]

I think I'll ask Dad to have a look at the EEC sender in question. Where is it located on a '96 or '97 V8? Is the layout similar to a '95 4.6 or does anyone know?

 

[raider82]

Thank you all for your help with this problem. I'll tell Dad about this right away. One last thing, though. What would I need to test the EEC sender?

 

[Stinkfist04]

I don't know what kind of voltages it should be putting off. Someone might be able to chime in on that.

 

[Peter M]

One thing I didn't see was the milage on your car. My 'Bird now has just over 100k on it, and I was having overheating problems similar to what you are describing(minus the fan thing). I would consider checking the water pump. Time, corrosion and buildup will reduce the impeller efficency over time. It's a fairly simple fix, and should take care of temps while the car is moving. The fans do practically nothing when the car is in motion. But, if the coolant isn't moving too well.... you get the idea.

Peter M

 

[dDUBb]

I wasnt talking about the AC system .. I meant, if you turn the AC knob, the radiator fan should turn on.
Even driving on the freeway, when the fan wasnt working, the engine got extremely hot and boiled over, the fans have alot to do with cooling, even when the car is moving.

- Dan

 

[Rolling-Thunder]

I recommend that you get the codes read, and then post them here. You don't need to rent a code scanner, as some places like AutoZone will scan for free.

I say this becasue you don't sound 100% sure as to why the CEL is on to begin with.

 

[Stinkfist04]

Yeah def. get that light checked. There's a good possibility the light and the problem are related. Did the light come on around the same time you noticed an issue?

 

[master486]

Well the following things must be working properly for the fan to come on: PCM, constant control relay module, coolant temp sensor, the fan circuit, and the fan motor itself. There is also a fuse in the underhood power distribution box (60A, #5) for the cooling fan. It's hard to say what the problem might be, but here's a quick way to test it out. Unplug the coolant temp sensor and then turn on the engine. You'll get a code for it but without this sensor input, the PCM turns on the cooling fan as a fail-safe. If it does turn on, then everything in the circuit is working properly and the temp sensor is probably to blame. If it doesn't come on, try tapping the CCRM (relay box between the right headlight and airbox) and see if the fan comes on. If it doesn't, carefully wiggle the connector to the fan. If it still doesn't come on, check that fuse. Also, check for voltage to the fan with a multimeter. There are two power wires, one for low-speed and one for high-speed. The colors are dark blue and brown w/orange stripe, respectively. Check both for power. If there's no power to either wire with the sensor unplugged (or A/C on as mentioned above), there's a problem with power to the fan, and if the fuse isn't blown I'd suspect the CCRM.

And as the others said, you should still get that CEL checked out.

 

[mikemelancholic]

So if something is wrong with the electric fan, could that cause a CEL? I've just noticed that if I leave my car idling in the driveway for any longer than 10 minutes, the temp gauge starts climbing and I get nothing from the electric fan. Coincidentally, I just started getting a CEL. Could these two things be related? If that would throw a code, any ideas on what the code would be?

 

[General Zod]

just get the code read

 

[Rolling-Thunder]

Why is it more and more people are reluctant to get the codes scanned?

Why do you want people to GUESS as to what the problem might be?

The CEL comes on to alert you to a problem with the car.

A simple scan - which can be obtained for FREE - will certainly make it easier for us to help you in determining what to do next.

 

[mikemelancholic]

I'm not reluctant. Right now my car overheats after 10 minutes. I'm not going to drive it to the nearest AutoZone and risk damaging the car just to get a code read until I replace my fan. I thought maybe somebody would know whether or not a bad fan motor would throw a code and would like to share. Instead I get replies like "just get the code read". Gee I would have never thought of that! I know my electric fan's motor is bad (gets voltage but will only rotate after nudging it). All I want to know is... will a bad electric fan motor cause the car to throw a code? I'm in the process of replacing the fan. As soon as I swap it, I'm going to get the code read, just as I had planned. In the meantime however, I was curious as to whether or not anybody knew. Not a big deal. This board is getting so damn hostile its ridiculous.

 

[The Great Obucina]

Why is it more and more people are reluctant to get the codes scanned?

Why do you want people to GUESS as to what the problem might be?

The CEL comes on to alert you to a problem with the car.

A simple scan - which can be obtained for FREE - will certainly make it easier for us to help you in determining what to do next.

because they arent very smart and refuse to listen.

 

[Rolling-Thunder]

I'm not reluctant. Right now my car overheats after 10 minutes. I'm not going to drive it to the nearest AutoZone and risk damaging the car just to get a code read. I thought maybe somebody would know whether or not a bad fan would throw a code and would like to share. Instead I get replies like "just get the code read". Gee I would have never thought of that!

You said in a previous post that your car overheated if left idling in your driveway for 10 minutes. I took that to mean that you were still driving the car around - but only if you didn't let it idle first for 10 minutes.

You also said the CEL just started coming on. This again implies you've been driving the car around with this overheating condition. Hence my comment.

Maybe your thermostat has gone bad. Without knowing the current maintenance history of your car, it's hard to just guess over the internet.