sixdogs
Super Star Member
- Joined
- Dec 8, 2007
- Messages
- 13,644
- Location
- Ohio
- Tractor
- Kubota M7040, Kubota MX5100, Deere 790 TLB, Farmall Super C
I have a 5520 Deere that turned over but wouldn't start so I checked the fuse panel and the 20 amp fuse was blown. Changed the fuse, cranked again and blew the fuse. Again changed the fuse but just turned the key to "on" and blew the fuse. Now what?
After a fair amount of searching, I learned that if you have a 5000 series Deere like my 5520, it might have the cold start feature. This is a little electric sending unit that tells the tractor it's real cold out and advances the timing. When these things fail--and they do--they dead short, blow the ignition fuse and the tractor won't start. The temporary solution is to unplug the unit from the harness and tractor will start--until it gets cold again.
The sending unit is on the inlet water neck going into the block. There are two sendng units on this water inlet. The bottom one goes to the temp gauge and has a sending unit on it. Forget that one. The top one is a little button thing that is shown in the picture below. Part #is RE503242.

This unit is on lots of Deere tractors with the cold start feature and I would have posted a list but the Deere site is down. But know the cold start thing is an option/accessory and doesn't show in my parts book as a part of the basic tractor. So you could well have a different tractor and have this switch on it.
I post this because a sending unit like this would not normally blow a fuse but this is connected to the engine fuse because it advances the timing in cold weather. Few would ever think to look to this sending unit but would spend hours searching. Now you know where's Waldo.
After a fair amount of searching, I learned that if you have a 5000 series Deere like my 5520, it might have the cold start feature. This is a little electric sending unit that tells the tractor it's real cold out and advances the timing. When these things fail--and they do--they dead short, blow the ignition fuse and the tractor won't start. The temporary solution is to unplug the unit from the harness and tractor will start--until it gets cold again.
The sending unit is on the inlet water neck going into the block. There are two sendng units on this water inlet. The bottom one goes to the temp gauge and has a sending unit on it. Forget that one. The top one is a little button thing that is shown in the picture below. Part #is RE503242.

This unit is on lots of Deere tractors with the cold start feature and I would have posted a list but the Deere site is down. But know the cold start thing is an option/accessory and doesn't show in my parts book as a part of the basic tractor. So you could well have a different tractor and have this switch on it.
I post this because a sending unit like this would not normally blow a fuse but this is connected to the engine fuse because it advances the timing in cold weather. Few would ever think to look to this sending unit but would spend hours searching. Now you know where's Waldo.
Last edited: