The rheostat when it goes bad creates high resistance, this in turn means the switch has to "pull" more power to work. The switch wil then over time heat up and start to melt. This is what I believe happened to my 81 Imperial. Both the switch and connector were melted and the wire harness that runs along the top of the left fender also over heated and the fusable link burned thru. I had to have the headlight wire harness replaced from the switch to the lights. One of the other signs is the headlight doors open very slowly or not at all. I also believe that Chrysler used the same headlight switch on all it's cars of this period. According to several parts stores here (NAPA,Checker,AutoZone and CarQuest) they list the same switch for the Cordoba/Mirada/Imperial, Dodge Diplomat/New Yorker/Fifth Ave/Fury. The issue I have with this is that the Imperial headlight doors are opened and closed by an electric motor where as the others are not. This also draws more power thru the headlight switch which I don't think can handle it. As a side note when I drove the car for the fist time at night and they went out I pulled off the road and installed a replacement headlight switch for my 94 Dodge Dakota, it worked! I may put it back as the Dakota with it's Halogen lights pulls a lot of power and it has a higher rated fuse than my Imperial. When I had this repaired the dash was removed from the car and the wire harness inside as well as under the hood was inspected for possible shorts. None were found. The only defect found was the burned headlight switch and connector which the owner of the repair shop said he has repaired on many Chryslers just like mine. I looked at several 80 thru 83 Cordobas and Miradas in the salvage yards here in New Mexico and every single one had the same burned headlight switch and connector. Makes me wonder if Chrysler made these cars to last only as long as the warranty did! I can only make a SWAG (sorry military term) as to the cause of my problems as the original owner parked the car in 1991 when the headlights started to go out. Dave U. 81 Imp > What are the first signs??? > > The problem was the dash was going blank when the > lights were switched on, fault was in the rheostat part > of the switch that dims the dash, first signs of this > was that at certain points of rotation of dim function > the dash would go blank then with another small > twist it would come back on again. > Eventually it gave up the ghost altogether and > would not come on at all when lights were on. > > > Neil Thorpe, black imp 82 > > ----- Original Message ----- > From: <stealthloader@xxxxxxxxxxxx> > To: <mailing-list@xxxxxxxxxxxxxxxx> > Sent: Sunday, September 15, 2002 6:14 PM > Subject: Re: IML: 81-83 headlamp switch and disapearing dash display > > >> Check the rest of your headlight wire harness!!!! These cars are >> known >> for problems and this is one of the first signs!! >> Dave U. >> 81 Imp >> > Hi all, >> > >> > Fitted new headlamp switch Mopar # 56021898AB >> > old switch no # 4221248. >> > >> > Headlamps worked fine now as before problem was >> > when switching lights on the dash did not dim it >> > went blank this has been a problem for about two >> > years as speedo cannot be read at night. >> > >> > I just went outside now it's dark to see if all is well, >> > i switched the headlights on, dash went out >> > disappointed you bet then the dimwit in the >> > drivers seat remembered the dimmer switch >> >> >> >> >> >> >> > turn >> >> >> >> >> >> >> > turn >> > >> > Houston we have a glowing dash!!!!! >> > >> > The feeling of awe lasted err seconds. >> > >> > So if you have a dash that gets scared when it >> > gets dark buy it a new headlamp switch. >> > >> > Neil Thorpe Black 82 imp bravely driving into the night >> > London England. >> > >> > www.imperial82.pwp.blueyonder.co.uk >> > >> > >> > >> > > >