[W126 Coupe] Phoenix Relay Set-Up

[Dick Spellman]

Hi Iain,

No reason, just a stock of that particular type of gear used to test 
designs for older analog set-ups I use from time to time.

Regards,

Dick

Iain Gunn wrote:

> Another link for Bosch style relay revealed

> http://www.classictruckshop.com/clubs/earlyburbs/projects/bosch/relay.htm

> ----- Original Message ----- From: "Iain Gunn" <igunn at bmts.com>

> To: "Mercedes Coupes Mailing Lists" <mbcoupes at mbcoupes.com>

> Sent: Friday, June 20, 2008 10:50 PM

> Subject: Re: [W126 Coupe] Phoenix Relay Set-Up

>

>

>> Dick, is there a reason you use this relay rather than a standard 

>> Bosch style relay?

>> http://www.wiringproducts.com/index1.html

>>

>> Iain

>> ----- Original Message ----- From: "Dick Spellman" 

>> <spell.yy at verizon.net>

>> To: <jralex at ix.netcom.com>; "Mercedes Coupes Mailing Lists" 

>> <mbcoupes at mbcoupes.com>

>> Sent: Friday, June 20, 2008 12:22 PM

>> Subject: Re: [W126 Coupe] Phoenix Relay Set-Up

>>

>>

>>> Hi Jim,

>>>

>>> I've attached a jpg image of the 12 volt, 10 amp rated relay I use with

>>> a map of terminals to wiring.

>>>

>>> For purposes of understanding what you are creating....you are

>>> effectively energizing the relay coil when the compressor kicks on and

>>> this results in the Normally Open to Common circuit on the relay

>>> switching to CLOSED allowing the positive side of the fan circuit to be

>>> completed hence, the fan kicks ON.  The trigger for energizing the 

>>> relay

>>> is off of the tapped lead (1 of 3) attached to the back of the Denso

>>> compressor.  You have to tap the correct wire obviously.

>>>

>>> So, rather than wait for the fan pressure switch on the receiver/dryer

>>> to call for added cooling sans the aux fan, you have added cooling at

>>> all times so long as the ac compressor is on.

>>>

>>> I will attach an image of the relay wired in place in a second email 

>>> soon.

>>>

>>> The aux fan for other running conditions such as the 110C manifold

>>> sensor continues to behave as before when AC is not in use.

>>>

>>> Regards,

>>>

>>> Dick

>>>

>>> jralex at ix.netcom.com wrote:

>>>> Dick, I am interested in the fan wiring info. Send to: 

>>>> jralex at ix.netcom.com. Thanks! J. Alexander

>>>>

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

>>>>

>>>>> From: Dick Spellman <spell.yy at verizon.net>

>>>>> Sent: Jun 19, 2008 3:48 PM

>>>>> To: Mercedes Coupes Mailing Lists <mbcoupes at mbcoupes.com>

>>>>> Subject: [W126 Coupe] Phoenix Relay Set-Up

>>>>>

>>>>> If anyone is interested,

>>>>>

>>>>> I have photos and mapped the hook-up needed for a Denso compressor to

>>>>> always run the aux fan circuit so long as AC is selected.  I'm 

>>>>> doing the

>>>>> write-up this weekend for Jonathan and sending him the relay I use 

>>>>> for

>>>>> this purpose as a thank you for all his techy and parts support.  

>>>>> This

>>>>> is my third hot weather set-up of this kind.  It was originally

>>>>> prescribed by Stu Ritter and I have just given it the nick-name 

>>>>> Phoenix

>>>>> because it's always steammy there in the summer months.

>>>>>

>>>>> Amazingly, the coolant temp never leaves the top of the 80C 

>>>>> indicator on

>>>>> these M103 motors with this set-up and this naturally assumes all 

>>>>> other

>>>>> components are in good service order like visco, tstat, radiator, 

>>>>> water

>>>>> pump, belt tension and so on.

>>>>>

>>>>> Take care and stay cool.

>>>>>

>>>>> Dick