electric diagnosis pleeeaasse....

[timb2117]

Ok here goes - 2005 K series 1800. Couple of weeks ago following a rare full car wash, it wouldn't start, click, nothing. Rocked in gear tapped starter zero.

The battery was U/S so just bought a new shiny one and fitted - same. Starter tested off car A1.

The grey 30A relay in engine bay is changed & new as there is power reaching it, but it doesn't do anything when ignition is turned.

The Bosch 40A one in car (top pic) is the source of the click but I cant seem to get a reading for input or output power from it with my tester. - is there an idiots way I can test it off car?

Starter is receiving 12V through the large cable, but obviously zero through either of the two smaller switching wires - which seem to come from the 30A relay.......

Is it relevant that the cars not been started for 3 weeks whilst waiting for the new battery to arrive? Have I killed an internal back up power source in the ECU?

Errr any help from someone smarter than me (yes that's like all of you :)) would be thoroughly appreciated.

thanks Tim

 

[SM25T]

Remove the small cable from the solenoid on the starter motor. Fit a female spade connector to a new piece of cable. Connect this to solenoid. With car in neutral and ignition on, touch other end of this new cable firmly on to the + terminal of the battery. Expect a spark. If the starter cranks the engine, you know your problem is in that cable or the starter relay. You can bypass the tiny relay in the MFRU box if necessary with an external 4 pin 12V relay.

[anthonym]

this isn't deathly click is it? .. though it sounds more like a flooded relay ;-)

"Have I killed an internal back up power source in the ECU?" No. There isn't one.

"The grey 30A relay in engine bay is changed & new as there is power reaching it, but it doesn't do anything when ignition is turned." Is it really receiving a 12v feed? (tester should tell you). Swop it for another new one and see? Does it's earth work?  Is it wired right? Sounds odd..

and check the purple 12v feed wire connector... 2005 is just right for all sorts of electrics fun.

is that relay in the engine bay the "relay mod" hoped to solve the click of death? So check if the thin wire SM25 above is talking about and see if it is stiff. Check the voltage it can carry, or indeed just replace it, rule it out as a culprit as they tend to get fried over several or many years. They suffer from "heat soak" where as the wire stiffens the ability to conduct reduces, last one I had like that was sent 12 volts and delivered only 7v which isn't enough to click the solenoid. Not sure your car develops so much heat though. edit: sorry I misread 1800 as 1600. 

WATER: a fuse?

Just for interest here's an MFRU diagram:

Anthony

 

[timb2117]

brilliant thanks guys more to track down

[anthonym]

all good fun, I enjoy it except when it's a necessity! :-)

Many of us just know about our own experiences (so that's me), there are some who are encyclopedias of 7 wisdom. 

[timb2117]

Thanks Anthony, sm25, -  shes working!

I ended up with 2 new relays and new wiring runs, still zilch, for some weird reason the relay in engine bay had switched power but no power feed I have no idea (premature alzheimers?) as to how that occurred but soon as rectified fires like a dream.

I guess when push comes to shove after hours of fiddling go back to basics and start again.

Thanks again Tim