[W126 Coupe] Suspect OVP relay (old subject-sorry)

[Afzaal Khan.M]

Vance
 sometimes the OVP  relay has a cold solder joint  on the diode
connection inside.car ,the fuse was ok.resoldered everthing back and
all is well
regards
mak


On 11/06/2009, Vance Rowley <vance.rowley at tiscali.co.uk> wrote:

>

> Hi Mike,

>

>   Yes, the fuse is OK, and the voltage with the engine running seems OK at

> 13.9v. Also, thanks very much for the offer of the OVP, but unfortunately, I

> am located in the UK (although I do sometimes visit Vegas each year in

> November during the Global Gaming Expo), sadly I don't think I will be going

> this year, and of course I am hoping to get the problem sorted before then

> anyway. Thanks again for the offer, all help is always appreciated. I must

> remember to look you up next time I visit.

> One more thing is, I have noticed there are a few variations of the OVP

> (different part no's, some with one fuse, some with two), but from what I

> can tell from the little circuit diagram on the side of my relay (201 540 32

> 45) and comparing it with the photos of others I have looked up on the net,

> it doesn't look as though it makes any difference as long as it will fit

> into the socket. In fact when I looked up my part number on a UK based parts

> supplier, it returned part no 201 540 37 45, one with two fuses and a red

> top with an additional circuit which would be redundant if plugged into my

> socket. From what I can tell, this should be fine as the first circuit looks

> the same. Am I correct about this?

>

> Cheers,

> Vance

>

> ----- Original Message -----

> From: Mike R.

> To: 'Vance Rowley' ; 'Mercedes Coupes Mailing Lists'

> Sent: Thursday, June 11, 2009 2:44 PM

> Subject: RE: [W126 Coupe] Suspect OVP relay (old subject-sorry)

>

>

>

> Have you checked the fuse in the OVP? A blown fuse will create the high idle

> (BTDT.

>

>

>

> What's the battery voltage with the engine running? When my ABS & Battery

> light come on at the same time, my alternator has died and the battery

> voltage is too low.

>

>

>

> Where are you located? I think I have an OVP you could borrow/buy.

>

>

>

>

> Later,

>

> Mike Ramay

>

> (702) 494-8056

>

> Las Vegas

>

>

>

>

> From: mbcoupes-bounces at mbcoupes.com

> [mailto:mbcoupes-bounces at mbcoupes.com] On Behalf Of Vance

> Rowley

> Sent: Thursday, June 11, 2009 5:56 AM

> To: Mercedes Coupes Mailing Lists

> Subject: [W126 Coupe] Suspect OVP relay (old subject-sorry)

>

>

>

>

> I know this subject has been covered many times, but there doesn't seem to

> have ever been any exact diagnoses, and appears to be some confusion on the

> subject.

>

>

> The symptoms are as follows on my 1991 560 SEC (Euro).

>

>

>

>

>

> 1. Takes a long time to start, (where it used to start on the first couple

> of turns of the engine.)

>

>

> 2. High idle, around 1400-1600 rpm (and sometimes creeps up).

>

>

> 3. ABS and ASR warning lights on all the time.

>

>

> 4. Hesitate slightly when you hit the gas. (more noticable when you rev the

> engine in neutral)

>

>

>

>

>

> This I believe is the typical (limp home) mode. I have seen these symptoms

> on many forums as well as our archives, but never usually all at the same

> time. Also, these symptoms that other people have are usually intermittent,

> where mine are permanent. Anyhow, there are quite a few different diagnoses

> for these symptoms around on the net, but mostly point towards the

> overvoltage protection relay. I have of course checked the fuse in the top

> of the relay and is OK, as well as making sure the pins are clean, which of

> course they are. Have even tried one tip to disconnect the battery overnight

> to try to reset the system. No joy.

>

>

>

>

>

> My main question (before I purchase a new OVP relay) is, can anyone confirm

> that this is the problem for sure. Also, I unplugged the relay and started

> the car and all the above symptoms remain the same without the relay even

> plugged in. This got me thinking. Does this mean if you unplug the OVP relay

> on a known good working car, that you will get all the above symptoms? This

> would surely confirm the diagnoses and was wondering if anyone has done it.

> If so, please let me know, as well as any other tips or hints.

>

>

>

>

>

> Thanks,

>

>

>

>

>

> Vance.

>

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