• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

T-Series Heater Switch Question

Share this page

tony barnhill

tony barnhill

Great Pumpkin - R.I.P
Offline
Heater Switch Question

I hate working under a dash...but, today I decided to tackle repairing the clock in my '79 MGB; however I couldn't get to it so I removed the blanking plate covering the rectangular hole right over the heater switch to the right of the clock...

.....still couldn't get to it so I removed the heater switch.....UH-OH!! Bad move!!

I don't recall that the heater switch has ever been out of the dash & it was so brittle that, as I pulled it out, it disintergrated in my hands....oh, darn!!

Well, at last I get the clock out, repair it ala Jack Laird (works great now!) and, after a couple of hours wiggling it, finally get it back in the dash.

So,I pull a new heater switch off the shelf & go to install it. Now, here's my problem:

...the wiring diagram says there's the plug to the back of the heater switch plus a red/white wire for the light...however, I have the plug, the red/white wire & a black wire...& my old switch is in pieces so I can't tell where the wires went except it appears the 2 spades that could be used for the red/white or black wires are the same - just one on each side of the switch....UH-OH!

Does the black wire go to the heater switch or did I pull it off something else nearby? Man!

(Oh, & I really HATE messing with things electrical!)
 
Re: Heater Switch Question

Tony your mistake was trying to repair the clock. You know you always have to leave something not working, or something else will break
 
Re: Heater Switch Question

My clock is still working and keeping good time Tony. Good stuff.
 
Re: Heater Switch Question

!!!! The same thing happened to me Tony! I wanted to figure out why my 3 position fan switch only intermittently worked in one position and the thing fell apart in my hands when I started to think about removing it!

Luckily, you had a switch you could send me, and that one has been working perfectly since I installed it a over a year ago now. /bcforum/images/%%GRAEMLIN_URL%%/laugh.gif
 
Re: Heater Switch Question

Black wire is a ground. I can't recall a ground wire being switched on any B... it's the ground side of the lightbulb in the switch. Shouldn't matter which way you connect 'em.
The bulb won't care. /bcforum/images/%%GRAEMLIN_URL%%/smirk.gif
 
Re: Heater Switch Question

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]You know you always have to leave something not working, or something else will break [/QUOTE]

Case in point - the heater switch fell apart in my hands! hehehehe
 
Re: Heater Switch Question

There shouldn't be a ground at the switch...the heater circuit ground at the motor end. Could that ground be for the clock?
 
Re: Heater Switch Question

I'm sure the heater motor is power switched and has its ground at the motor itself, but how does the internal lamp in the switch get its ground?
 
Re: Heater Switch Question

See, the wiring harness argrees with what Joe said...that's why I was wondering whether I'd pulled the ground wire off something else while my hand was up under the dash...but I don't know from where.
 
Re: Heater Switch Question

Does your switch have an internal light?
 
Re: Heater Switch Question

The little word "Heater" only
 
Re: Heater Switch Question

My switch has an internal light, but I think it gets it's power from it's main power source. I don't remember a separate wire for the lamp....but it's been about 5 years since I was in there...
 
Re: Heater Switch Question

IIRC, the internally lit ones were on the rheostat with the rest of the instrument lighting: red/white is V+ from it. Switch is plastic with no other ground source for that lamp.

I may be remembering something from another car, though. It's been years and many, many different vehicles.

<shrug>
 
Re: Heater Switch Question

Tony
I just installed that switch which I bought from you. The red/white wire goes on the side closet to the speepo, and the black wire goes on the other side. Mine is a 1977 but should be the same. The ground is for the light in the switch btw
Dave
 
Re: Heater Switch Question

Daqve - that's what I ended up doing though on the '79 it doesn't show the black wire on the diagram...thanks
 
Re: Heater Switch Question

Ah-hem...
 
Back
Top