1989 M998 stupid question

[CaptainChaos]

What is this? Mine is unplugged and I can’t find any info on it. New to these so take it easy on me.

 

[ehinlein]

What is this? Mine is unplugged and I can’t find any info on it. New to these so take it easy on me.
View attachment 931311

Cadillac valve and time delay module. Should be controlling hydraulic fan clutch on /off. Uses p/s brake hyd pressure.

 

[Thunderbirds]

When i got my truck in May this year this was also disconnected and I had to ask. I just recently plugged it back in and it seems to work fine, more testing and trouble shooting to be done to find out why it was disconnected. I assume to keep the cooling better as it was used in a desert environment. But that is just my best guess. I am waiting to something to stop working.

Here is a picture of the parts manual. The Cadillac valve is on another page I can't find right now.




EDIT:

Found the Part # in the TM for the Cadillac Valve:

 

[CaptainChaos]

When i got my truck in May this year this was also disconnected and I had to ask. I just recently plugged it back in and it seems to work fine, more testing and trouble shooting to be done to find out why it was disconnected. I assume to keep the cooling better as it was used in a desert environment. But that is just my best guess. I am waiting to something to stop working.

Here is a picture of the parts manual. The Cadillac valve is on another page I can't find right now.

View attachment 931312


EDIT:

Found the Part # in the TM for the Cadillac Valve:

View attachment 931313

Cool, at least it's not a major deal if it's unplugged. I appreciate the response. I think I will plug mine back in as well to see what happens. I assume this was also used in the deep fording system to disengage the fan as to prevent the blades from breaking as they hit the water.

 

[TOBASH]

You may have a bad unit. They may have unplugged it to force the fan to stay on because it was not turning on or activating properly previously.

If you reconnect that, watch your engine temperature very carefully and take your vehicle for a drive at highway speed, being prepared to pull off and unplug that unit at the first sign of high engine temperature.

 

[CaptainChaos]

You may have a bad unit. They may have unplugged it to force the fan to stay on because it was not turning on or activating properly previously.

If you reconnect that, watch your engine temperature very carefully and take your vehicle for a drive at highway speed, being prepared to pull off and unplug that unit at the first sign of high engine temperature.

Copy that. That is what I was thinking as well. I am already OCD about watching gauges, so I'll catch it quickly if it is faulty. Thought about trying it in the driveway but I doubt it would get warm enough to tell even at high idle.

 

[TOBASH]

Copy that. That is what I was thinking as well. I am already OCD about watching gauges, so I'll catch it quickly if it is faulty. Thought about trying it in the driveway but I doubt it would get warm enough to tell even at high idle.

Exactly correct about driveway.

This will most likely require freeway/highway over 50 MPH.

IMHO