Mopar Muscle Association UK

we are working on a 68 charger with factory A/C the heater control in the dash is U/S . can any body tell me if i need to find a control valve with the same numbers on as this one, as i am confused with the amount of different ones ,there are some new valves on the net that very in price a lot

The very first job I ever did on my mopar...

These switches work in two parts. One of them is an electrical switch for the heater blower and ac pump and if you look inside you'll see there are various sector plates that move left and right when you press the buttons in the dash that operate the vacuum part of the switch.
All these sector plates do is to open and close an orofice to allow various sets of vacuum servos under the dash to see vacuum from the resevoire in the engine bay. These vacuum servos then act on the various doors in the heater box to direct the air.
These switches all have different combinations of sector plates. If you hook the wrong switch up to the car it may well physically fit but the combination of sector plates may not neccesarilly give you what you'd expect from the markings on the push buttons as who knows what combination of vacuum servos will be activated?

Match the numbers up to your replacement switch and put it back together and it should work assuming there are no vacuum leaks.
Oh and 1 last tip.... don't throw away any bits of foil - they are important for the backlighting and you can't get replacements.

I should add it's the top number that matters - thats your mopar part number. I believe the bottom number is like some sort of batch code.

I had similar issues with a wiper switch and refused to pay the crazy money for a repo one.

In the end, i used a rotary switch which using diffrent pin out ultimately allowed me to get the correct pinout required.

Work really well and quality is great and hidden under the dash but I get you after original ...

https://uk.rs-online.com/web/p/rotary-switches/1935733/

thanks for the help will have to keep looking for one with the correct top number

use ebay to look for

mopar (3895790, 2820487, 3431020, 3895033)

all are improved versions of what you have that are less likely to fail

3895790 is the newest you can use potentially made late 70s early 80s. supply is good as the things seem to have been almost single use

just cut and paste my search in big font above into ebay

basically there are 2 types of switch with the same number of front push buttons

1 has its vacuum pipes in that v shaped pattern of 7
and one has its pipes in a rectangle pattern of 8 and the electrical connections are different

any v shaped pattern with the right number of push buttons on the front is good
the search above focuses on this type, the 8 pipe one is a different range of numbers and was used on cars in the 80s

then just never press any of the buttons hard. soon as you do you crack the back off and you have an expensive vacuum leak again

i'd guess that there are so many switches under different numbers becasue they had to keep upgrading it or the glue they used, as people expected electronic switch action from a very slow vacuum operated switch, and basically hammered them and broke them. Numbers beginning with 2 are usually early 60s, numbers beginning with 3 are usually late 60s to mid 70s, most parts had a couple of numbers in their life, this switch seems to have LOADS which in my mind would indicate that it was a bit rubbish.


use this advert and pictures to cross ref yours with one from my search, any will do.

https://www.ebay.co.uk/itm/NOS-Mopar-5- ... :rk:1:pf:1


they are usually 60 - 80 quid and its a waste of time ever buying anything other than a new one...
As you have found i'm sure, you only take these out when they are busted so anyone who has one taken out of a car for second hand sale is selling a busted one.....

I have 2 or 3 purchased from people on here and at the NATS and not one of them worked properly, all second hand junk

hence when i can be arsed to pull the dash i'll buy one off Rick ehrenberg he seems to know a good one.... (see the ad. i link to)

Dave

thanks for the info ,have desided to get a new one from Jeff at 521 restorations
dose anyone know of any speedometer repair shops

Hi Rob, been thinking of contacting this lot:

Mike Flannery,
Flannery Speedometer Repair,
Tel 01594 861095
Mob 07910 287721
Gloucestershire.
http://www.magnetic-speedometer-repair.com/

spoke to them at the NEC last November. Not tried them yet tho.

regards, Stu.