Cooling Fans

[brarei200]

I have a 1995 Pontiac Trans Am 5.7 and it overheats in stopped trafffic. I think it is the cooling fans not working. I have a SLP Manual Fan Switch and sometimes it works and sometimes it don't. I tested the fans with the laptop and confirmed they both work at high speed. When I flip the switch it makes the passenger side headlight flicker. With the SLP Fan Switch the computer should still turn on the fans automatically and the switch just lets you turn it on whenever. So I'm not sure what's going on. If it matters I have the driver side headlight motor off for repair right now. Also for some reason the driver side turn signal flashes with the car off and with the key off. The car has a new cooling system. It has a new BeCool Radiator, radiator cap, tuned for a 160 thermostat, hoses, water pump, new sensors for the cooling system, basically everything was overhauled in the cooling system about a year or two ago. No signs of coolant in oil or vice versa. Thanks for the help!

[popo8]

Hello Brandon. First lets start with the thermostat... u said u have a 160 thermostat on the car. Are u sure it is not malfunctioning?

Next what temp to you have the fans set to go on?

Have u tried actually watching the fans to see if they are actually spinning?

LTXtech.com IS my drug...
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[brarei200]

I assume it is working but have not tested it since it was installed but I did put the thermostat in hot water and watched it opened before I put it on about a year ago or so.

The fans are programmed to come on early, the previous owner had it done so I'm not sure what the temp it is programmed at.

The last time I had it out I left it running in the driveway while I was going to open the garage door and I came out to the car and it was a little over 210, I checked the fans and they were not running.

Thanks

[popo8]

Ok... so ur issue is that the fans are not turning (based on the comment about when it hit 210).

Have u checked fuses and relays?

LTXtech.com IS my drug...
OWNER/ADMIN

[brarei200]

Yes, fuses and relays are good.

[Injuneer]

In the 95 with the low speed/high speed control, the ground for both fans comes off the right side fan. Make sure the black wire from the A pin on the right side fan is connected solidly to a chassis ground. You may have disturbed it with the headlight work.

You indicate you used a computer to confirm both fans run at high speeds. Do you mean that happens when you flipped the SLP switch? Remember, if you are reading fan status from the PCM, what you see is the indication of the PCM commanding the fan on via the relay. If the relay circuit does not respond, a code sets. There is no feedback to the PCM that the load side of the relay has actuated the fans. Note also that the fans get 12V from a fusible link at the red "+" box near the battery. Need to check the fusible link.

Shoebox has the fan control diagram. Use "late production". Early production only applies to 1994's. GM failed to delete that part of the diagram when they included it in the 95 factory manual.

http://shbox.com/1/1995_pcm6.jpg

[popo8]

This guy knows his shyt^^^

LTXtech.com IS my drug...
OWNER/ADMIN

[brarei200]

I will check the ground. I used GaryDougs OBD1 program from FBN, there's a fan on/off switch actuator in the program to turn them on. When I used that, the fans worked but they failed to work with the SLP Switch. Thanks for the diagram I'll look it over

[Injuneer]

Correct.... Gary's Scan9495 will do that. Just needed to know that was how you checked the fans.

Using Scan9495, start the engine, run a log, and watch the two columns for fan relay 1 and fan relay 2. They will indicate "0" until the PCM commands the relays on. Then they indicate "1". Watch the CLT temp and let the engine warm up until it hits the max temp at idle, which you indicate is 210*F. That will tell you if the PCM tried to turn the fans on at lower than stock program temps (226*F for low speed, 235*F high speed). When it reaches max temp, you could even block air flow to the radiator to see when the PCM does try to turn them on. Verify the PCM CLT temp is reasonably close to the dash gauge reading.

Don't use the fan switch while doing this.

If you want help with the data log I can look at it.

[brarei200]

I should have time to check it out this weekend and get the log file to you.

Thank you

[JCzNova]

Welcome to the forum. When you have time maybe you can swing by HERE (http://ltxtech.com/forums/forumdisplay.php?4-Introductions) and tell us a little bit about yourself and your TA.

[brarei200]

I got a chance to data log it, anyone want to take a look. Thanks!

http://s000.tinyupload.com/index.php?file_id=06136222513055637139

[GaryDoug]

Brandon, when you get a chance download the newest version of Scan9495. What version are you using now? The one you are using is old and definitely has some bugs. The newest version has some new features also. Fred can still view your file using Excel, but I usually use Scan9495 to view them and that won't work with the old version log files.

[brarei200]

Its probably close to two years old. Ill get the new version

[Injuneer]

I'll take a look at is as soon as I can, but I can't believe how many of these I get to look at. Is anyone else reviewing these, or am I the last one? Better train someone, because at my age, senility can't be too far away..... LOL.

[Injuneer]

Went to download, but got this from Norton:



Dangerous Website Blocked


You attempted to access:
http://s000.tinyupload.com/index.php?file_id=06136222513055637139

This is a known dangerous website. It is recommended that you do NOT visit this site. The detailed report (https://safeweb.norton.com/report/show?url=http:%2F%2Fs000.tinyupload.com%2Findex.ph p%3Ffile_id=06136222513055637139&product=N360&version=22.8.0.50&lang=0901&source=toolbar)explains the security risks on this site.

For your protection, this website has been blocked. Visit Symantec (http://sitedirector.symantec.com/932743328/?ssdcat=316&?langCulture=en-US)to learn more about phishing and internet security.




Exit this site (http://about<strong></strong>:blank)
Continue to site anyway (http://www.norton.com/co/viewanyway)

[GaryDoug]

. I downloaded it with no issues but can't post a csv file here so I renamed the file with a .txt extension.

[brarei200]

download garys txt file and rename it with .csv extention

[GaryDoug]

Brandon:
1. Your version of Scan9495 is too old to see the fan relays. It only shows the variable readings. Get the new version.
2. You need to run the scan longer. You scan is only 5 minutes long and the engine temp stays at about 183-185 the whole time, maybe too low to turn on the fans.
3. It would help to have the scan running when you see the problem.

[Injuneer]

I'm going to hold off until we get the required info in the file.