90 Overheating, Fans not operating
Thread Starter
Intermediate
Joined: Nov 2006
Posts: 26
Likes: 0
90 Overheating, Fans not operating
The temperature gage on my 1990 L98 almost pegged (just touching the warning area) without the fans comming on sitting in traffic. I asume they should have. I switched on the A/C and it cooled right down to mid-gage level. Thus the fans work. I checked the fuse, it was okay. Per the wiring diagram the only other elements in the circuit are two relays and the ECM to ground the relays. I would check the relays If I knew where they were located. Can someone provide me with the location of the relays and/or any other possible problems?
Racer
Joined: Dec 2004
Posts: 470
Likes: 0
From: Phoenix Arizona
I have a '90 also, and overheating is an issue, the relays are located on the drivers side of the radiator shroud. Very inexpensive to replace Autozone, Pepboys, or your local dealer.
Hope this helps...........................
Hope this helps...........................
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
You wasted your time checking the fuse, because you knew the fans worked by turning on the A/C. Now you want to waste more time checking the relays you also know work? How hot is, "The temperature gage on my 1990 L98 almost pegged"? Was it really "Overheating"? Were the fans even supposed to be on? Don't you have a digital temp gauge besides that analog gauge? Before you can say it over heated (short of a disaster) you have to know how hot it got. Before you can say the fans are broken, you have to know if it was hot enough for them to be called upon. If you don't have a digital gauge, you will have to utilize an independent mechanical gauge to find out just what is happening.
RACE ON!!!
RACE ON!!!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Mileage
I would check the relays If I knew where they were located.
Originally Posted by redvtt
First, read in your manual how to test the relays. It's very easy test to do.
Originally Posted by Mileage
I switched on the A/C and it cooled right down to mid-gage level. Thus the fans work.
RACE ON!!!
Thread Starter
Intermediate
Joined: Nov 2006
Posts: 26
Likes: 0
Thanks jghmcz06, redvtt and FCI-EFI,
I know very little about auto electrical systems in general and less about the system in my new '90 vette, thus my post here. I tried to include as much info as possible to those who might wish to help including that the fuse was good.
No, I do not know if it was hot or not. Just that the gage was well above where it normally runs with the t-stat controlling the temp. Personally, I just don't like my engine temp gage to be near the max safe indication. I neglected to mention that the oil temp was also higher than normal for my engine. I do not have a backup gage for that either.
No problem hooking up a mechanical gage to see what is going on. It would be easier and maybe better to hook my laptop up to tha ALDL to see what the ECM thinks the temp is and compare that to the .bin settings for fan1 and fan2. I should have thought of that sooner and not wasted FCI-EFI's time. At least now we know that the one fuse and set of relays is the ONLY way to turn the fans on. I mistakenly thought there could be additional relay(s) controlled by the A/C to turn the fans on. Thanks for the help.
I know very little about auto electrical systems in general and less about the system in my new '90 vette, thus my post here. I tried to include as much info as possible to those who might wish to help including that the fuse was good.
No, I do not know if it was hot or not. Just that the gage was well above where it normally runs with the t-stat controlling the temp. Personally, I just don't like my engine temp gage to be near the max safe indication. I neglected to mention that the oil temp was also higher than normal for my engine. I do not have a backup gage for that either.
No problem hooking up a mechanical gage to see what is going on. It would be easier and maybe better to hook my laptop up to tha ALDL to see what the ECM thinks the temp is and compare that to the .bin settings for fan1 and fan2. I should have thought of that sooner and not wasted FCI-EFI's time. At least now we know that the one fuse and set of relays is the ONLY way to turn the fans on. I mistakenly thought there could be additional relay(s) controlled by the A/C to turn the fans on. Thanks for the help.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Mileage
Just that the gage was well above where it normally runs with the t-stat controlling the temp.
Originally Posted by Mileage
I do not have a backup gage for that either.
Originally Posted by Mileage
It would be easier and maybe better to hook my laptop up to tha ALDL to see what the ECM thinks the temp is and compare that to the .bin settings for fan1 and fan2. I should have thought of that sooner and not wasted FCI-EFI's time. At least now we know that the one fuse and set of relays is the ONLY way to turn the fans on. I mistakenly thought there could be additional relay(s) controlled by the A/C to turn the fans on.
RACE ON!!!
