70 H/L & wiper vac

[Dennis D.]

Spending some R&R at my son's in NC. I use the super bowl as the excuse to come down. Not that I need one (as the wife says).

Before I left home I took the 70 for a little spin. I notice the headlights open very slowly from the light switch. If I pull the overide, they open fast and correctly. Before I tear the dash apart to start troubleshooting, I figured someone's "been there done that".

The issue with the wipers is after switching off the wipers get to just about the park posittion, and the door stars to close. Pulled the overide for this as well. Figured I'd tackle it once I got home. Thing I know where to look for this one, but.............

[Jack H.]

Re: 70 H/L & wiper vac

If you look at a vac diagram (usually given by various vac trouble shooting guides available from different catalog parts houses) you'll see the various mechanisms for opening 'things' (wiper door, headlights) are all devices that vent vac from the control line serving the target actuator. If any of the vac switches vent vac, the item opens... So, unless there's a problem with the rate of vac venting in your headlight switch, the headlights should open at the same speed whether you actuate them from the HL switch or from the over ride switch!

Now, if your system has leak(s), you might confuse cause & effect (which switch works better) with state of vac stored in your reservoir. More specifically, did you try the two switches in a sequence and perhaps NOT have given the system sufficient time to rebuild/recover vac in the storage reservoir? If so, you could be drawing an incorrect conclusion (one vac vent switch works better than another)...

On the wiper door, you're describing a typical 'cockpit' adjustment problem. The way the system is designed, the wiper door can NOT begin to close until the wiper arms are fully parked. The way the system 'knows' the wiper arms are parked is the RH arm presses against a vac switch that's mounted in the cowl when it comes to rest.

That vac vent switch has enlongated mounting holes in it to establish the correct geometry of when it 'fires' and allows the wiper door to begin closing. Sounds to me like your wiper door 'park' switch is mis-adjusted and needs to be positioned a little further down (toward the firewall) to make the wiper door close a bit later in the park cycle....

[Dennis D.]

Re: 70 H/L & wiper vac

thanks Jack. I suspected the cowl switch with the wiper issue. I don't believe its moved, but I'll try to adjust before I replace

I did try the 2 headlight switches consecutively several times. Going to see if I pinched a hose at the H/L switch, since that was the last part of the system I tampered with reinstalling the dash pad.