Hi all, I was wondering if any of you had experienced this strange heater fault, Nobody over here in the UK has had it happen.

I was driving the other week with the roof off & had the heater on full (well it was January in England)

I noticed the display on the heater went off, when it came back on the digital disply started scrolling round, & the LED's started flashing.

When I pulled up on the driveway, I turned the engine off removed the key & the heater blower was still running, I had to disconnect the blower to stop it.

Any idea's? i'm going to have a look this weekend.

Thanks, Kevv.

 

This just happened to my 89 vert two days ago. Maybe there's something going around! I noticed that a gentle knock on the carpet just to the left of the heater made it go back to normal. This makes me suspect a dirty and/or loose connector in that area. I hope I have some time this weekend to take a look.

 

Thanks if I find anything i'll let you know, luckily i'm removing that section of dash due to the fitting of an MP3, so I can take the heater unit out at the same time.

 

'89 Electronic Controls have a separate ground wire to the driver's side kick panel. That's where a bunch of others are grounded, though on a separate lug, so you might check it there. You need to remove the hush panel to see it. If the display came back to some number in the 70's and the blower doesn't work for a couple of minutes that usually means it's momentarily losing power or ground. If the ground is good, check the Connection at the Control Panel. If that's good, you usually need a new Panel (actually they're all rebuilt) or some take them apart and clean up the Contacts and Board with good results.

Blower speed - electronic controls - is controlled by a Module mounted on the Evaporator Case - right side of the Firewall (assuming it's still left hand drive). Through '89, low voltage signals are sent from the Controls (Brown or Tan Wire) to the Module and it amplifies those signals to control the speed of the Blower. The Dash Controls are the Processor for this Year and it was designed to monitor actual blower voltage. It gets this info through a 5 amp fused circuit spliced into the Blower Lead (Purple). If that fuse opens, you usually get nothing but high Blower and it may run with the ignition off. The fuse is on the Firewall so you might make sure it's not open. Just follow the Purple Wire from the Blower to find it. If good, and the blower is running on high with the ignition off, then it's usually the Module. That part is used on all electronic GM's, so it fairly easy to find.