Paul94Z28

Hello-

I am receiving a false low coolant light in my 94 Z28. When I follow the service manual, it says to unplug the sensor (light still on), then unplug the Retained Assy Power Module (light goes off). According to the manual, I should replace the RAP module and we should be all set.

Truth is, $76 and one RAP module later, I still have the problem.

Any ideas?

Any assistance appreciated.

Paul

blitzer454

What does the RAP look like? Is it the wiring that connects to the coolant level low sensor?

Do a search and you will find that the coolant level sensor has a history of failing on F-bodys. Either replace it or just leave it disconnected.

moparman

Just unplug the sensor.

TUFF LT1

Sometimes those sensors get gunked up with stuff, if you take it out and don't want to spend the money to get a new one...just cleaning it off can fix your problem. Just some info for ya.

OBE1 95Z28

As stated above, the sensor is a common failing item. Cleaning it may fix it, but it's not an expensive sensor. It's located right below the radiator fill neck and is easily access with the battery removed. You'll need to drain about half the radiator to remove the part. Shoebox has a good photo here:

http://shbox.com/1/low_coolant.jpg

Although unplugging it will eliminate the dash light, you also loss early warning of a true low coolant condition. Since overheating a car with aluminum heads can be a very expensive fix, I suggest you fix the sensor.

Injuneer

RAP is Retained Accessory Power module. That's the chip that controls the radio and power window power supply after the key is shut off, allowing them to work for another 10 minutes, or until a door is opened. Not sure why that would be connected to the low coolant light, but in fact if you look at the RAP module diagram on Shoebox's website, it shows a wire to the dash cluster, with the function "low coolant indicator control (latching)".

Courtesy of Shoebox:

http://shbox.com/1/rap_schematic.jpg
http://shbox.com/1/express_down1.jpg

While its possible the RAP module may be involved in the problem, its a lot more likely its a gunked up switch. I can see the logic in the diagnostic you are looking at though, because it appears if the "low coolant" light is on, it either means the low coolant sensor is faulty, or the RAP module is stuck in the "latched" position.

Try fiddling with the sensor.

Allen66

I've just had the same prob. with my Formula. The low coolant light came on, and the level was actually low. I topped off the coolant, and the light went off. I thought I had the problem beat, but when I idled in traffic tonight the light came back on. When I got home, the coolant level was fine if I read the level right. Also, the car didn't run hot or anything coming home either.

So is everything "cool" or not?

sscott

I had the same problem about two years ago, my low coolant light came on so I replaced the sensor. About two days later the light came on again I got a replacement sensor from the dealer at no charge and found out later before installing the replacement that I had a pin hole on the rubber tube that connects to the fill spout, the hole was located at the end where the clamp was attached. I just cut the tube at the hole and reattached it and filled the coolant to the proper level and I was good to go. The sensor ended up costing me $40 to $50 bucks.

Paul94Z28

Thanks for all the replies. I was able to isolate and remedy the issue.

As it turns out, it WAS the Coolant Level sensor and not the RAP sensor - hopefully they will take the RAP sensor back - it took them quite a while to get it to me as it is not a part that commonly fails. On a side note - anybody need a RAP sensor?

Thanks Again.

Paul

WestCoast96Z28

The beauty of the "search" feature. I was just about to start a thread on this, but decided to search first...and voila!!

I'm about 99.99% sure I have a bad sensor. My symptoms match what I've been reading.

Again, the Board comes through again...now if I can only get that SES light to stay off....

shoebox

Yeah, since there seems to be at least one question per day about the low coolant sensor.

Paul94Z28

Fixed - Thanks!