Hey all,

Noticed the other day that the truck would get hot when idling only, very intermittent, and would resolve once I started driving. Figured out that my auxiliary fans were not coming on when my AC was switched on. Did some investigating and it turned out that both of the auxiliary fan motors were shot. Replaced the motors and everything worked great.

Today, however, while lining up a trailer to back it into my driveway the temperature shot way up and was 3/4’s of the way to the top (usually temp only goes about halfway up the dial). This was my first time with a trailer and needless to say there was a lot of back and forth before I got everything lined up. When I turned the engine off I went to the front of the truck because per the manual and other threads on this forum the auxiliary fans should remain running when the engine is overheating, however this was not the case...

I know the motors are both good and they work every time I turn the AC on, but does anyone have an idea as to why they wouldn’t work after shutdown with an overheating engine?

 

You need to monitor the real time temp the ECU is seeing. DO NOT go by the gauge itself. It basically has 3 settings Off/Cold, Middle/Warm, and Max/ON FIRE..... Get yourself an Ultragauge, Scangauge II, or a bluetooth OBD2 unit and then monitor what the ECU see's. If I'm not mistaken on a D1 the fans will run if the engine temp is 212F or higher (might be off a few F's) and will remain on after the engine is shut off until it cools down.

 

It will remain on for 10 min and then the timer shuts off. This is the same problem I am fighting with. I found when my dash f=gauge gets above 3/4 the temp on my OBDII scanner shows 235F. my fans also do not come on with the AC compressor. Fans are controlled by the K109 relay and that is where I am at. I replaced the fan clutch with no noticeable improvement. Driving at slower speeds, around 35 or so, temp seems to run at about 205-210 which I think is too warm. Next I plan on replacing the temp sensor, and figure out where the K109 relay is. I know my truck has had a number of issues and i am working through them as I can. i guess that is the fun of owning one of these!!

Sounds like you may be having a problem with the timer module that controls the fans when the temp is high.

https://landroverforums.com/forum/di...e-high-100253/

 

if the relay was bad the fans wouldn’t be able to come on right? Have you tested the auxiliary fan motors themself?

 

Why not go off the gauge? I understand it’s not completely accurate, but it’s still a good approximation right?

 

No it is not a good way to monitor temps IMHO.

 

did you end up replacing your temp gauge to a more accurate one?

 

I use a Scangauge II to monitor engine temps, it plugs into the diagnostics port below the dash, or my OBD!! reader which has live data capabilities. I still need to get it up to temp and check with an external temp sensor.

The K109 relay (which controls the fans) is activated by the AC system, or engine temp (from ECU) or the temp sending unit. With ignition off, it is controlled by the ECU grounding the an control module, which starts a 10 min timer that engages the K109 relay. Per the Electrical Troubleshooting Manual. diagrams. I'd start with the temp sensor since you do get the fans with the AC on.

 

temp sensor or the fan timer module?

 

The gauge on the dash is nearly worthless. Your engine will be long over heated and head gasket cooked before you know it.

Here is a write up on using your phone as a temp gauge....

https://landroverforums.com/forum/di...02/#post581013


and here is the description of the function of the fans from the workshop manual (aka: RAVE)