790 electrical diagram-parking brake light stuckon

mountain_man · Jul 5, 2003

On my JD790, the parking brake light (instrument panel) is stuck on. The parking brake electrical switch is working correctly (tested with Fluke ohm meter when disconnected from wiring). Parking brake light still stays on even when switch is disconnected and switch wiring looks normal (not shorted).

Does anyone have an electical diagram for the 790 and can tell me if there is a relay between the switch and the light?

Many thanks,

zenmek · Jul 6, 2003

I'm gonna say (don't know if this is correct!) that your 790 probably has the same setup as my 770 /forums/images/graemlins/confused.gif. If it does, then under the dash panel is a black module that controls the flashing of the light, when engaged, and the lamp test portion with key on engine off. It is a sealed unit so no repair /forums/images/graemlins/mad.gif. If all else checks out then this would be your culprit! I don't have any schematics, but learned the hard way when mice got to my harness and shorted the thing out /forums/images/graemlins/crazy.gif good luck!

mountain_man · Jul 10, 2003

Thanks for your reply. Yes it appears the 790 is very similar to your 770. I've ordered a service manual (on CD) and will do some additional troubleshooting before I plunk down $130 for a replacement module. Hopefully the service manual includes an electrical diagram.

mountain_man · Aug 2, 2003

Just a follow-up on my last post. The parking brake circuit does have a relay/flasher which was defective ($33). The CD containing the JD CUT Technical Manual (P/N 1481) provides clear pictures, procedures, troubleshooting steps and diagrams (including electrical). Well worth $40!

zenmek · Aug 3, 2003

Where did ya get that CD at ? I'd like to see if they have one for the 770 /forums/images/graemlins/laugh.gif. Glad ya got the indicator fixed!!

mainiak1 · Aug 3, 2003

Mountain man,

You said you purchased a service manual for 790 on cd for $40.00. is this correct? Where did you purchase it?

Thanks,
Mainiak1

mountain_man · Aug 3, 2003

I ordered the CD through my local JD dealer (you can't order it via JD's 800 number). My dealer had not ordered the CD previously and fulfillment may be at the dealers "discretion". You might try a couple of dealers in case you local dealer is not accommodating. P/N is DB1481 - JD CUT Technical Manual. CD contain tech manuals for ALL of the following models:

655,755,855,955
670,770,790,870,970,1070
NEW 790
990 HC
NEW 4010
4100
4110, 4115
4200, 4300, 4400
Revised 4210, 4310, 4410
4500,4600,4700