# 1970 Lemans Wiring Diagram



## kenbaustin (Dec 24, 2010)

I'm looking for a wiring diagram with AC for my 1970 Pontiac Lemans. I trying to figure out why my blower control switch isn't working on all levels. I Replaced both the resistor switch and got a new AC/Heater under dash harness but I'm still having trouble when the switch is on low it does not come on. I'm new to this forum appreciate any help you can provide...


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## 1970 Lemans (Jul 25, 2009)

Losing just the lowest speed is, IMO, kind of unusual. Given all the things you have already replaced, I would look at the switch itself. Is there any corrosion on a contact that could be impeding current through just the lowest setting? If so, obviously just clean it up and see if that solves the problem. Could be internal, thus, if you really need (want) the lowest setting, you would need to replace the switch (~$40 through Ames or other).

I have had to replace my switch in the past because it was bad, but in my case I initially lost the highest blower speed (not an underhood fuse issue) and then the third speed and then the remainder.


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## kenbaustin (Dec 24, 2010)

Thanks for the reply... 

Here is what I hvae replaced so far....

AC/Heater Control Switch - bought new
Blower Resistor - bought new
AC/Heater under dash wiring harness 

I'm trying to find the wiring diagram with ac so I can see how the wiring goes from the switch to the resistor. There is a relay switch on my engine side of my firewall that I believe connects between the control switch and resistor. Would you have one? I found in one of the other post a wiring diagram without AC. I need on with AC. Thanks.


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## Eric Animal (Oct 28, 2007)

Ken, try www.ClassicCarWiring.com they make VERY nice laminated COLOR diagrams for most older cars. Not expensive either! Eric


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## 1970 Lemans (Jul 25, 2009)

This is from the 1970 Pontiac Service Manual. The manual also has a schematic for non-AC. I note from this later schematic that the blower motor switch only appears to have three blower speeds (as opposed to four for AC) with an additional off position. Is there any chance that you might have accidentally ordered the non-AC switch?


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## kenbaustin (Dec 24, 2010)

Thanks thats what I needed. My haynes manual didnt have that specific diagram and I was afraid to order one of those laminated ones until I talked to someone to make sure it had the ac wiring diagram. My switch has four speeds and its the correct one with AC. Looks like I need to look at replacing that relay and check all my wiring.


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## 1970 Lemans (Jul 25, 2009)

I believe the relay is for the hi setting only ... at least that is how I read the schematic. You may be right inre some wiring issue. Good luck.


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