aerocorey Posted December 13, 2008 Share Posted December 13, 2008 I got to thinking, why does there need to be a VSR for the rear defroster? There isn't one for anything else on the truck. Mine is bad, I decided to yank it out. Here's how to do it for those who aren't electrically inclined. Before you try this to fix your defroster you should make sure that the fuse isn't blown. If the fuse is good and you get a defroster light on the cluster with the switch on and your defroster doesn't work this could be the fix for you. -Pull the cluster out. -Lift the VSR and plug off of its perch on the firewall. -Cut all of the wires at the base of the plug. -Splice the 1 black wire and the 2 black/slate wires together. -Pop the hood and look for a single brown/black wire plugged into a 3 pin connector. The 3 wires are brown, black, and green. The brown/black wire will be lined up with the brown wire on the 3 pin connector. -Unplug the brown/black wire and zip-tie it out of the way. -Turn on the rear defroster while your hand is on the relay next to where the VSR used to be. Feel for the click. If it clicks...you're done. If no click you've got other issues. Quote Link to comment Share on other sites More sharing options...
western Posted December 13, 2008 Share Posted December 13, 2008 the vsr is in the circuit to prevent it being used when the engine is off & alternator is not charging, as the heater draws a fair current & disabling it & having the rear screen heater on without the engine running/alt. charging will drag your battery down fairly quickly. Quote Link to comment Share on other sites More sharing options...
Guest diesel_jim Posted December 13, 2008 Share Posted December 13, 2008 IIRC it was fitted to vehicles with a 45a alternator (my original 200Tdi had this), but looking through EPC (As i had then), vehicles with the 65a "heavy duty" ) alternator didn't have them. I would sometimes find if the engine was at tickover, with the lights/heater/stereo etc on, the HRW would turn off. when i upgraded alternator, i just made a little loop of wire with a male spade terminal on each end, removed the relay and plugged the wire into the two positions where the relay contacts would go. Quote Link to comment Share on other sites More sharing options...
aerocorey Posted December 13, 2008 Author Share Posted December 13, 2008 the vsr is in the circuit to prevent it being used when the engine is off & alternator is not charging, as the heater draws a fair current & disabling it & having the rear screen heater on without the engine running/alt. charging will drag your battery down fairly quickly. Leaving your lights on will do the same thing. The solution would be don't leave your RHW on with the engine off and the key on. There's even a bright amber warning light on the cluster. If you leave the key on with the engine off and that light telling you the defroster is on long enough to kill the battery you deserve to have to jump start your truck because you are an idiot. This is how I fixed mine without paying for a needless voltage switch. Quote Link to comment Share on other sites More sharing options...
aerocorey Posted December 13, 2008 Author Share Posted December 13, 2008 IIRC it was fitted to vehicles with a 45a alternator (my original 200Tdi had this), but looking through EPC (As i had then), vehicles with the 65a "heavy duty" ) alternator didn't have them.I would sometimes find if the engine was at tickover, with the lights/heater/stereo etc on, the HRW would turn off. when i upgraded alternator, i just made a little loop of wire with a male spade terminal on each end, removed the relay and plugged the wire into the two positions where the relay contacts would go. Definately an easier slution. Accomplishes the same thing. I found it handy to remove the VSR plug altogether because it gave me a place to mount the headlight relay. I also find it annoying to leave beind useless plugs and bits of wiring, but that's my problem. This is probably a better quick and easy fix than mine. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted December 13, 2008 Share Posted December 13, 2008 Like this in the tech archive Mo Quote Link to comment Share on other sites More sharing options...
western Posted December 13, 2008 Share Posted December 13, 2008 vehicles with the 65a "heavy duty" ) alternator didn't have them. my 110 had a 65amp on it's old TD engine & the 200TDi [now has a 100amp alt] had the VSR fitted, it's part of the rear screen heater wiring. Quote Link to comment Share on other sites More sharing options...
aerocorey Posted December 13, 2008 Author Share Posted December 13, 2008 Like this in the tech archive Mo Pretty much! Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted December 13, 2008 Share Posted December 13, 2008 It's always nice to have your own workings out confirmed by someone else Quote Link to comment Share on other sites More sharing options...
Cat_J Posted February 15, 2009 Share Posted February 15, 2009 If the light on the cluster doesn't come on could it still be just the VSR thats gone. Funny thing is that when I put the multimeter across the connectors on the window it shows a very low voltage but no light comes on on the instrument cluster. Quote Link to comment Share on other sites More sharing options...
western Posted February 15, 2009 Share Posted February 15, 2009 check the bulb works Quote Link to comment Share on other sites More sharing options...
dave88sw Posted February 15, 2009 Share Posted February 15, 2009 so is it a standard relay on the rear screen heater? i always thought it was timed to prevent the screen overheating and burning out. thanks if anyone can answer Quote Link to comment Share on other sites More sharing options...
western Posted February 15, 2009 Share Posted February 15, 2009 AFAIK it isn't a timer, but does have a similar function if the electrical loading from the alternator exceeds the VSR limit, it shuts the rear screen off, never got to that point with my 110 for it to do that, also see the reply's above Quote Link to comment Share on other sites More sharing options...
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