View Full Version : Cat D5 dozer warning light "!"

12-11-2011, 11:40 AM
I am preparing burn piles for our family property. When making short trips between piles, the dozer suddenly stops with the parking brake light shining along with the explanation point warning light. Dozer will not move and I shut it down and come back later and it is dead and requires a jump. Any thoughts? Thanks in advance!

12-11-2011, 12:56 PM
What model & Serial No Prefix of D5 ..?
If it's a fairly recent model with the electrically-switched parking brake and based on your symptoms that the machine is dead when you come back to it after leaving it for a while when it presents the problem you could have a problem with low system voltage when the engine is running, or possibly a bad battery.

12-11-2011, 01:34 PM
Model: 2006 D5G LGP; Serial No. Prefix: *MHK Thanks so much.

12-11-2011, 06:01 PM
Ah-ha. A full of electronics "modern" machine ......... if the tractor stops dead like the parking brake has been applied while the engine is running and then shows the Fault Light plus the parking brake light it could well be low on electrical power. The parking brake switch open/closed is actually 2 separate inputs to the Power Train ECM. If the system voltage goes low the ECM will not come out to play and thus everything stops. You say that the machine is dead & needs a jump start when you go to it later. Is it a bad battery/batteries or maybe a bad alternator. I would check the charging system before going any further.

When the machine stops does & the park brake comes on does the engine also stop..? If you try to restart the engine straight away does it start ..?

Of course I could be totally off base and it could be nothing more than a bad electrical connection in the Park Brake circuit or bad contacts in the Park Brake switch, but if that was true why are you having electrical low power issues with it not starting afterwards..?

By the way MHKxxxxxx is the Engine Serial #. The machine will be either WGB or RKG prefix. If you want a copy of the wiring schematic send me a PM with an e-mail address and your Serial Number.

12-11-2011, 07:33 PM
Thanks much!!! I am certain it is an alternator issue as it does not crank right back up. The engine keeps running, the hydraulics work but the dozer does not move when the described scenario occurs. I really appreciate your help and will try to provide the requested information to you asap!! Have a great evening.

12-16-2011, 08:57 AM
On your machine both the parking and service brakes are electronic. I agree with above that it sounds like an electrical issue. Are the batteries original? Does it start normally ever or does it always need to be jumped?

Scrub Puller
12-18-2011, 01:10 AM
Yair...As an old dozer/scraper hand who has never run "modern" equipment it seems quite amazing that brakes on a dozer are electronic...why?

Is there a significant improvement in performance and if so how...I mean a brake is a brake and I don't recall too many problems with the mechanical/hydraulic units of the past...it seems that electronics would be another layer of complexity to cause problems.

I would imagine that the useful life of modern machinery is compromised by aging and rubbing and wearing electric/electronic components.

Any comments?


12-18-2011, 02:22 AM
Couldnt agree with you more, give us some thing like a 6D 7G 8H 9 G/H the electrics were to start it and run the A/C if u had one and the lights every thing else was mechanical or hyd assist, cant get rubbed thru wires or bad connexions with them. RDG.

12-22-2011, 09:45 AM
IIRC, the brakes are electronically controlled because there are no traditional brake pads; all braking is done hydraulically by the drive pumps/motors. As they are electronically controlled it was much simpler to make the brakes part of that system instead of adding extra hardware and another whole system.

Scrub Puller
12-22-2011, 04:06 PM
the brakes are electronically controlled because there are no traditional brake pads

Yair...this is the question I'm asking on another thread...that is to say, do all these "improvements" lead to more production and less maintainance costs in the real world...from an owners point of view.

I know if I was looking to buy a machine I'd be looking for the least amount of electronic controls. I have a mate with three stickshift D8h's and they more than pay their way. He knows them inside out and there is not a component he can't rebuild in his remote location...not so if he had to deal with and trouble shoot electronics.