lol a UK gremlin has been borne over the weekend under my bonnet.

I noticed today that my wipers on low setting go up the windshield fine, but on the way back delay and are slow about half way on thier trip. No biggy... but then I started to hear a "beep!" everytime it did. I was like, wtf is that?

Then I noticed, my scan guage was resetting itself everytime the wiper went back down lol.

Anyone ever had this happen? I didn't think/get a chance to increase the speed of the wipers to see how they are doing, but I checked fuse 19 and all is good. Guess I'll see if I can find the ground strap pictured in the rave diagram on the wipers. I really don't feel like taking all that cabin air filter crap off though lol, hope its visible with some pushing and shoving only.

 

How very interesting...

My Scangauge acted up yesterday as well... raining, wipers were on. I didn't put two and two together, now I'm very curious if it was only when I was using the wipers?! I just unplugged it.

I'll go check mine out!

Dave

 

I'm intrigued now. I can't get my ultragauge to hook up anymore. it searches for what type the obd2 is, occasionally finds it, but still will never get all the way to the gauge screens... It turns on whenever I plug it in, but it's as though it's losing connection over and over.

I keep forgetting to swap it into another vehicle and verify the ultragauge didn't die... What's happening on your end GrandKodiak?

Dave

 

For wiper interaction -

The OBDII port and the wiper ECU and a few other things share a ground (earth) header C0551. A second ground from the OBDII socket also goes to earth header C0017. If the ground from the header to chassis was loose, current could flow thru the OBDII wiring and over to the second ground. Results would depend on the internals of the OBDII device. May want to check these two connectors attached.

For won't find ECU -

The OBDII port has signal lines that are ganged together on header C0286. They go to a whole bunch of computers, not just engine management. If one of the computers has a ground, or gibberish noise on that line, it will prevent the OBDII device from yacking with the engine computer. The header is under the interior HVAC fan, and has mostly pink wires.

Note: The word "computer" is used to describe these modules. No, they are not an Ipad with 128 GB, or an IBM ES9000 (air cooled), or Data General. Just poor little microprocessors trying to do a job. Some cars now have them for each seat belt tensioner. Eventually vehicles will have these for everything, so they can tell the techncian what to replace. At that point the the art of the mechanic and the diagnostic skill will be reduced to nothing. The vehicle will be diagnosed by a computer elsewhere, via the "cloud", while you are driving to the dealership. When you arrive the parts will already be waiting at the assigned service bay.

 

Sorry if I'm being thick here - is it showing that this shared ground C0551 is located under the carpet in the drivers footwell?

Dave

 

That's where the RAVE shows it to be, I have a D1 so can't peek. The RAVE circuits manual show the map (wiring diagrams) with small numbers at ends of wires that indicate connector number and pin. The electrical library lists all the connectors with a pix of location usually, in the world's cleanest Rover, kept in a big jar with no oil or dirt on it.

 

Your battery voltage is to low, the wipers are drawing all the power and your OBD port is going dead from lack of power.
Start with a charging system check.

 

The discovery I has a fuse just for the OBDII power.
The Discovery II may have the same fuse...

 

A variation of Spike's idea would also be if the ground that is shared by them is loose and has built up corrosion and resistance. Then when the wipers run, that extra resistance kills the voltage to those devices, just like a dirty battery cable will kill it to the starter. The corrosion creates a series resistance, and 10 amps of current thru a 1/2 ohm resistance will produce a voltage drop of 5 volts.

 

Battery and alternator power are fine, checked the kick panel connectors they where all tight, not lose wires, no bare wires, kinks, debris etc, checked the ground strap above the cabin filter (tiny wire, but its intact, clean and attached)... checked the underhood fuse panel (no blown, lose or otherwise out of the ordinary things appearing there). checked all the visible earth grounds in the engine bay just for ****s and giggles, along with the main harness which i had troubles with 2 years ago when i bought it... no problems there that i could see.

I checked under the carpet for the last ground but there is nothing under the carpet but metal... no leads, no wires......?

Also, I noticed that the power is fine as the wipers go UP, the problem is only when they try to come back down... and that the power to the obd2 port flickers as the wipers stutter on the way down. it only happens on the first speed (slow) setting, they work normally and dont interrupt the obd2 until they are put back in slow mode or are turned off and go back down slow.

Thought... do these vehicles use wiper relays? ive had experience with sticky relays in other vehicles in the past that often manifest themselves in "power ticks" similiar to how i would describe this.

ps i foudn this on the interwebs:

"The wiper relay on a discover II is on the fuse box under the steering wheel. It is however an integral part of the fuse box and is not a replaceable unit. The fuse-box will have to be replaced. Wipers also use the auxiliary relay. This is R7 and is located in the engine compartment fuse-box. Try replacing this with another relay of the same value from this fuse-box (temporarily) and see if your problem disappears."

heres some more found info for future searchers... guess ill start lookin at these wires more specifically:

Slow speed operation

Operation of the front screen wash/wipe switch to the slow wipe position, connects the feed

from fuse 19 in the passenger compartment fusebox to the front screen wash/wipe switch

on a GS wire, via header C0292.

The feed passes through the slow wipe switch contacts and is connected to the windscreen

wiper motor on an RLG wire. The windscreen wiper motor is connected to earth header

C0017, via header C0288 on a B wire. The feed is connected to the slow speed brushes

within the motor and operates the motor at slow speed.

Fast speed operation

Operation of the front screen wash/wipe switch to the fast wipe position, connects the feed

from fuse 19 in the passenger compartment fusebox to the front screen wash/wipe switch

on a GS wire, via header C0292.

The feed passes through the fast wipe switch contacts and is connected to the windscreen

wiper motor on a ULG wire. The windscreen wiper motor is connected to earth header

C0017, via header C0288 on a B wire. The feed is connected to the fast speed brushes

within the motor and operates the motor at fast speed.