LS1LT1 Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
1,092 Posts
Discussion Starter #1
the last few days my low coolant light has been coming on sometimes and i thought maybe it was low so i added coolant to the resouviar (radiator was full) and it still didn't go off. then it randomly went away. now i notice that when i turn on the key, the low coolant light will come on the dash and sometimes go off like normal but sometimes stay on. if i turn off the key and turn it back on sometimes i can get hte light to shut off, other times it just stays lit.

this sounds to me more like an electical problem with the sensor rather than the coolant level itself correct? i was going to try to reach down and unplug it and clean the connector but i can't get the damn thing unplugged since there is a hose blocking my fingers from getting to the connector. maybe if i remove the battery....

has anyone else had random Low coolant lights for what appears to not be an actual low coolant problem?
 

·
Registered
Joined
·
1,092 Posts
Discussion Starter #3
well i went and got a new sensor and some coolant and a syphon to try to get enough coolant out of the radiator to get the sensor out. well i got some out but apparently not enough cause as soon as i took the sensor out coolant started pouring out onto my garage floor.

i got the new sensor in and coolant in and battery back in and turned on the ignition only to find i had no coolant light whatsoever. not even during the test period like the bad sensor :mad:

so i pulled the car out of the garage removed the battery and proceeded to dump more coolant on the ground as i put the old sensor back in (after trying to clean it)

i thought that worked except after 2-3 tests the low coolant light stayed on solid again like it had been doing so i said **** it and just unplugged it. luckily i was able to get my $54 back on the stupid defective sensor.


why the hell is one small sensor so damn expensive anyway?
 

·
Global Moderator
Joined
·
13,428 Posts
Here's a tidbit of info probably long forgotten. If your car has a rap module, it's involved with the low coolant sensor system.

If your car has no rap module, it has a low coolant sensor latching module, tucked under the dash.

In 95 service manual, it is discussed in the troubleshooting chart 15 on page 8A-81-23.

If your without the 95 manual, you can download the 94 in the 4th gen section. Look for thread titled "GM service manuals". Pretty sure 94 manual will have the same troubleshooting chart.
 

·
Registered
Joined
·
1,092 Posts
Discussion Starter #5 (Edited)
I do have a RAP module. I had to change it a few years ago.

Are u sure you mean RAP module and not body control module BCM. I don't see how the RAP module would have anything to do with the coolant sensor since the rap only keeps power to stereo and windows after the car is shut off. Fwiw mine blew during a window fix install cause of 2 similar color wires hooked up wrong. I lost power windows and the stereo. I know the BCM replaced the RAP and several other modules for 1996.
 

·
Global Moderator
Joined
·
13,428 Posts
95's don't have a bcm. I'm just passing on the info I gleaned from the troubleshooting chart I found in the 95 manual.

It beats me how the rap module is involved, but as stated by manual, cars without rap option have a low coolant sensor latch module, whatever that is.

I will try to find more info on the subject.

Here's the chart for members viewing. I know it's small, but that's the best I could make it.
 

Attachments

·
Registered
Joined
·
1,092 Posts
Discussion Starter #7
Yeah I know 95's don't have a BCM I thought that all 93-95 had the rap module but I guess maybe if they didn't have power windows or something maybe they didn't have one?
 

·
Global Moderator
Joined
·
13,428 Posts
Just found out what the latching module does. If your car doesn't have a rap module, you have the latching module. With rap the latching module is built into the rap.

On 96-97 cars latching module is built into the bcm.

So here's what it does. It prevents the low coolant light from flickering when light is on. It also keeps low coolant light on, regardless of coolant level, once sensor turns low coolant light on. It keeps light on until ignition is turned off.

So once you turn off ignition, fill radiator, coolant light will stay off, at least it's supposed to.
 

·
Registered
Joined
·
1,092 Posts
Discussion Starter #9 (Edited)
According to that chart my sensor is bad. The one i replaced it with was also bad as it wouldnt light up for the test or when i plugged it in when the sensor wasnt even in the radiator. So now im back to the original sensor unplugged. Not sure if its worth $50 for the sensor.
 

·
Global Moderator
Joined
·
13,428 Posts
Many members find it easier to just unplug the sensor and live without it. Most gear heads check their fluids on a regular basis, so unless a catastrophic failure occurs, coolant level will always be OK.
 
1 - 10 of 10 Posts
Top