Heater doesn't stay warm. rear defrost dash lights not working.

[D Loco]

It's a 1990 tsi ive checked fuses and all look good. My heater blows but when it's on low it will start out blowing warm but it will start to get cooler and the higher i turn up the fan the colder the air gets. also rear defroster light will come on but the defroster itself wont work. My dash lights have never worked since i bought the car tail lights weren't working either my mechanic fixed those and thought he might have fixed the dashlights too but couldn't tell ### it was bright out. Could any of this be caused by my alternator not providing enough juice. i have a 900 watt amp hooked up.

 

[Ultimate1]

If you leave it on low air power does it stay warm forever? Or does it get cold eventually as well?

 

[supraevo87]

no that amp wouldn't keep the dash lights from coming on i have a 1200wat amp on mine and it just dims my lights a little. As for your heat problem it sounds like a heater core problem check your coolant levels and if they are where they need to be replace ## heater core.

 

[crash89]

Check your coolant level. My bet is you are low!

 

[TSIturbo91]

Check your coolant level. My bet is you are low!

Yup sounds like a low coolant level.

 

[1983gsp]

Stuck or no thermostat.

 

[DzMiniz]

.Check the connector on the rear hatch glass.
theyre common for breaking off

 

[dsmAB]

Stuck or no thermostat.

Yea most likely that. Same thing happened to me, and found out that my car didn't have a thermostat in it.

 

[TSIturbo91]

Yea most likely that. Same thing happened to me, and found out that my car didn't have a thermostat in it.

Also check condition of coolant refill cap. Mine was probably original and had a slight leak. Caused me to replace the thermostat when it wasn't bad. But that wasn't a big deal.

 

[D Loco]

Even on low it starts to get cool but it will stay just a little bit warmer than air outside. if i leave the vents set to outside air but leave fan off the air that blows through my vents while i'm moving is warm. I just put in a brand new 180 degree thermostat.because it had a 160 in it but no difference did the exact same thing. my coolant levels fine. my first thought was heater core. but also my radiator fan is not set on a relay it constantly runs from the time i start the car till the time i shut it off. but theres another thing that made me think it might be alt and it depends how loud i bump my system sometimes i get low power cuts to it. like the amp looses power for a minute then comes back and i know i'm not straining the amp. plus when i tried to recharge my ac this summer when i turned the ac over to full blast the car would die. i knew the dashlights werent out from the alternator they didnt work when i bought the car. the only gauge thats lit when i turn my lights on is the aftermarket boost gauge. The clips yall are talking about on rear window are they the ones on the sides of the glass or do i need to pop panels off because those looked fine.

 

[DSM1G90]

T-stat needs to be 195*. the 180 is too cold for the motor to operate properly.

Heater core is prob full of corrosion (mine is the same ) and a full dash pullout is needed to get to the heater core to either take it out and head to a radiator shop to have it boiled out, or a replacement.

tried to recharge my ac this summer when i turned the ac over to full blast the car would die

Welcome to the world of 4cyl cars with AC ... they don't like each other.

Compressor really take a lot out of the motor just to turn it around. With six pistons in that compressor pushing and pulling the R-12

(and if you shoved in R-134, major problems will result since the compressor wasn't designed for R-134 unless a rebuild is made for the newer oil . Also, did you add Compressor oil before the recharge? With all of those pistons inside, they need oil as well, just like the motor does..this is prob why it dies on you..possibly burning up the compressor)

, it really saps the power off the front of the crank.

True, the wiring traces on the back windows will break without any visual evidence, or one of the leads that goes back to the glass has broken off the glass since they are just soldered on.

-DSM

 

[TSIturbo91]

T-stat needs to be 195*. the 180 is too cold for the motor to operate properly.

Heater core is prob full of corrosion (mine is the same ) and a full dash pullout is needed to get to the heater core to either take it out and head to a radiator shop to have it boiled out, or a replacement.

Welcome to the world of 4cyl cars with AC ... they don't like each other.

Compressor really take a lot out of the motor just to turn it around. With six pistons in that compressor pushing and pulling the R-12

(and if you shoved in R-134, major problems will result since the compressor wasn't designed for R-134 unless a rebuild is made for the newer oil . Also, did you add Compressor oil before the recharge? With all of those pistons inside, they need oil as well, just like the motor does..this is prob why it dies on you..possibly burning up the compressor)

, it really saps the power off the front of the crank.

True, the wiring traces on the back windows will break without any visual evidence, or one of the leads that goes back to the glass has broken off the glass since they are just soldered on.

-DSM

Just to elaborate on your explanation. If R134a is put into our system before it is retrofitted it will turn the oil acidic and ruin the compressor and the whole system will need a flush. The oil for R12 is mineral based and R134a is a polyester oil. They're not compatible. Also R12 is banned by the EPA now so a retro fit is worth it if your want AC.

 

[DSM1G90]

Thx for the explanation in more greater detail.

What I heard that the compressor have to be rebuilt with new seals to accomodiate the R134a oil, along with any joint with a seal that the seal has to be replaced to be compatible with R134a, otherwise the R134a will destroy that original seal in due time.

 

[gusu]

The rear defrost may be easy.

There is a wire on the hatch that can come unplugged easily, if that happens simply plug it in. If the light is coming on that would be the first place I would check.

 

[D Loco]

The rear defrost may be easy.

There is a wire on the hatch that can come unplugged easily, if that happens simply plug it in. If the light is coming on that would be the first place I would check.

I couldnt find this wire. Where is it located on the hatch? Both clips are still sodered on windshield and both have wires plugged in them.

 

[DSM1G90]

..that's what he meant - the two wires-one on each side of the window.

Take a VOM and red to the clip and black to the hatch mechanism (ground) turn the motor on and press the defrost button.

Check your voltage this way to see if you got power coming up from the front.

If so, then we've "condemned" this section of the circuit - it'd be the window itself.

(If you don't have a VOM and good with a solder iron, solder two wires on a 12v bulb - one to the base and the other to the brass case - a simple bulb makes an excellent 12v tester..)

-DSM

 

[D Loco]

..that's what he meant - the two wires-one on each side of the window.

Take a VOM and red to the clip and black to the hatch mechanism (ground) turn the motor on and press the defrost button.

Check your voltage this way to see if you got power coming up from the front.

If so, then we've "condemned" this section of the circuit - it'd be the window itself.

(If you don't have a VOM and good with a solder iron, solder two wires on a 12v bulb - one to the base and the other to the brass case - a simple bulb makes an excellent 12v tester..)

-DSM

don't have a vom or a solder iron can probly find one in the next couple of days. so if i'm not getting enough power to the clips would that be a wireing problem between the button and rear window or would that be the case if i'm getting no power at all? and if i am getting power does that mean i'll have to completely replace that window? also i never gotan answer if my radiator fan constantly running could cause my heater to do what it's doing?

 

[Ultimate1]

It sounds like to me like your heater core might be plugged and the blower motor easily cools it down.

 

[DSM1G90]

also i never got an answer if my radiator fan constantly running could cause my heater to do what it's doing?

Two things: either you got the AC button pushed in and when you turn the fan switch on, this fires both fans to run constant, or: You got a fan relay stuck closed (or someone pulled the relay and replaced it with a jumper wire to keep the fan running constant and no, this wouldn't have effect on the heat issue outside of that colder 180 t stat which isn't allowing the coolant to get as hot as it should ) - which the relay is located under the relay box next to the passenger strut tower.

mean i'll have to completely replace that window

Take it to a glass shop and they might be able to do a trace repair. Otherwise, the window will have to be replaced.

So, if I'm not getting enough power to the clips, would that it be a wiring problem between the button and rear window, or would that be the case if I'm getting no power at all? And, if I am getting power, does that mean I'll have to completely replace that window?

You answered two of your own questions here ...

Good luck in your search - DSM

 

[D Loco]

Two things: either you got the AC button pushed in and when you turn the fan switch on, this fires both fans to run constant, or: You got a fan relay stuck closed (or someone pulled the relay and replaced it with a jumper wire to keep the fan running constant and no, this wouldn't have effect on the heat issue outside of that colder 180 t stat which isn't allowing the coolant to get as hot as it should ) - which the relay is located under the relay box next to the passenger strut tower.

Take it to a glass shop and they might be able to do a trace repair. Otherwise, the window will have to be replaced.

You answered two of your own questions here ...

Good luck in your search - DSM

Thanks. I bet rear defroster is a wiring problem.Seems ive been diagnosing them since i bought the car. will use a vom or lightbulb and find out for sure. fixing to buy a 192 t-stat so i'll find out if thats the problem. if not guess i'll take it to a shop and have them check my heater-core. i'ld do it myself but pulling out the dash sounds big. And the luck i have better not do it myself because it seems everytime i pull a panel off i break it. I know its off subject but i'm a noob and i have a couple of questions. the hose for the vacuum on the back of head is non-existent and oil has sprayed on back of motor where the injectors are. if i buy a hose to put on this where am i supposed to run this hose? and theres a hosecoming off the side of the head that the vacuum is on that is not coneected to nothing and i don't know what it's for. are these what you hook up an oil catch can too? saw a pic of another bay and these lines were hooked up to something that looked like a can.And also can someone tell me what crankwalk is and what it means if your car does it.from posts i've read all i can gather is that its really bad. Oh yea i don't push the ac button when running heater. when i hit the button is the only time when the ac fan runs. Radiator fan runs constant though. relays bypassed like u said thanks for telling me where to locate it though. should it be hooked up or is it better if fan runs constant?

nevermind on crankwalk found info on it. Still need to know where to run a hose on my vacuum so it will quit spraying oil on my injectors.

 

[D Loco]

i'm guessing heater problems is due to heater core was a little low replaced the tstat with 192 heater is a lil warmer now but real good yet theres no power to readefrost clips.

 

[DSM1G90]

A relay controls the current to the rear def clips, that is activated by the button on the dash.

Relay prob under the same cover with the AC fan relay.

Just check to see if the relays are seated in their sockets, and/or look at the relay map on the cover to see if the relay is there.

It's actually a 196 degree "T-stat", not 192...

good luck-DSM