syoo8

It's been raining heavily here in Central California over the last week.

Everything has been running normally, until...

Drove home from work today (about 15 minutes ago) and turned the ignition off. Car was STILL RUNNING. Dash looks like it is about 1/2 brightness. Then I smell an electrical smell somewhere in the car, can't seem to locate it. I intentionally stall the engine, then disconnect the battery in back, run inside to post on Rennlist.

Any ideas on what is happening here?

Scott

neilh

Water leaked in behind the fuse / relay ( CE) panel maybe - pull back carpet on passenger side and look for water - windshield seal / rain channels or whatever blocked or leaking ...

Mrmerlin

do you have a hot post cover?
Is the car out of the rain?
Is the CE panel wet?,
you might see water dripping from above the CE panel is it coming in from the blower box ?
Was the battery ground strap wet?

syoo8

Hi Neil and Mrmerlin-- thank you for your help!

Car is still outside, but it has stopped raining.
I do have a hot post cover.
Battery ground strap (which I disconnected to "turn off" the car) was dry.
CE panel is dry. No water visible.

anpo

Is rain water really conducting enough to create this kind of short? However moist and relays aren't the best of friends. Maybe one of them, like the X-relay, just got stuck? Try tappin all relays on CE-panel.

jon928se

It was raining you had the rear screen on right ?

Check the Rear screen demist button isn't stuck in.

If it isn't, unplug the relay for the rear demist - you'll have to look that one up for your year.

Both the above can cause the car to continue running after the ign is switched off. Th3ey effectively back feed +12v into the ingition circuit.

My money is the on the relay - the elec smell was the electrons escaping.

pcar928fan

I was also thinking it might simply be the ignition switch...those things do go out and when they do there is NO TELLING how they will fault the system!

Mrmerlin

Jon thats an interesting diagnosis I forgot about

syoo8

Bingo. Car starts fine, stops fine. The demist button was stuck in about a 1/4 of an inch but I didn't notice.

1) Does the smell indicate that I've burned through the demist relay?
2) How did you know that the demist button was the culprit?
3) When 928s were new, were they susceptible to these electrical gremlins, or are they principally a result of dirty ground points and corroded terminals in the CE panel?
4) When 928s were new, were they susceptible to water leaking on the CE panel?

5) You people are all so brilliant. I read EVERY POST on this board DAILY (because I only get to drive my 928 a few months out of the year) and I am stunned by the level of expertise on RL. I especially enjoy the arguments (e.g. to Porkension or Not To Porkension.)

Thank you all so much for helping with this...

pcar928fan

I'll be damned! That is the first I have heard of this one! Great work John! I never use mine, so it never gets stuck in...

jon928se

Common problem in the UK (where I'm from) where it Rains most of the time - demist gets used a lot, pod warps a bit, button sticks.

The timer in the relay can also stick (when you turn the demist on by EDIT Pushing rather than twisting EDIT) - however diagnosing this is tricky - the relay unsticks when you remove power totally ie. dis the battery - unfortunately for easy diagnosis when the run with no key symptom occurs the 1st thing that happens is to dis the battery. (AFTER YOU'VE STOPPED THE ENGINE BY STALLING IT)

Andre Hedrick

Dang !!! That was an amazing diag.

I have to get one of those jousting sticks so I can be as smart as you, Jon!

anpo

How do one stall an auto trans? If the same will sometime happen to me, just got a bit curious.. Remove fuse or relay for fuel pump will do the work but I'm looking for at solution my mother or girlfriend could handle.

SeanR

Wow Jon, thanks for that one, looks like we learned a new one today.

Thank you.

jayc67

Looks like one more reason for a master battery cut off switch. I think this thread has pushed me over that edge.

Cut off switch going in mine for sure now.