Is it the blend motors???

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AntS70

AntS70

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Birmingland
Every now and then the book symbol comes on but all seems to be working fine. If i switch the engine off and restart it dissappears. What i did notice is with the heater on hi it does blow hot, but when i knock it down one notch to 28 it is noticabley cooler not just 1 degree cooler, more like 5 or 6 degrees cooler, does this imply the blend motors are on their way south or somethng else?
 
AntS70 said:
Every now and then the book symbol comes on but all seems to be working fine. If i switch the engine off and restart it dissappears. What i did notice is with the heater on hi it does blow hot, but when i knock it down one notch to 28 it is noticabley cooler not just 1 degree cooler, more like 5 or 6 degrees cooler, does this imply the blend motors are on their way south or somethng else?
Click to expand...


ant m8, you need to meet up with john (irishrover) when he comes over to visit his family, he's got the diagnostics to check them for ya. he had a look at mine over xmas.. PM him and ask him when he's coming over and if he's bringing his swag. nice bloke ;)
 
Put HEVAC into manual mode then drive the temp. controls for both sides through the range from HI to LO a couple of times. Do the same with the distribution control from floor to screen. Unless you have a compressor, next time you go for juice or check the tyres, get the air line and blow through the small grille just below the time clock on the dash. You say that when you go from, I think, HI down to 28 that you get a drop. HI is max-not 29 or 30 etc. it is the temp. blend flap motor fully open. Is the temperature the same both sides when you select the same value ? The Hevac will do self check function automatically and clear any "Non hard" faults.
I shall be over around March and will bring the Rovacom with me if you wish-just PM me
 
mark1971 said:
ant m8, you need to meet up with john (irishrover) when he comes over to visit his family, he's got the diagnostics to check them for ya. he had a look at mine over xmas.. PM him and ask him when he's coming over and if he's bringing his swag. nice bloke ;)
Click to expand...
Cheers Mark, will do.;)

Irishrover said:
Put HEVAC into manual mode then drive the temp. controls for both sides through the range from HI to LO a couple of times. Do the same with the distribution control from floor to screen. Unless you have a compressor, next time you go for juice or check the tyres, get the air line and blow through the small grille just below the time clock on the dash. You say that when you go from, I think, HI down to 28 that you get a drop. HI is max-not 29 or 30 etc. it is the temp. blend flap motor fully open. Is the temperature the same both sides when you select the same value ? The Hevac will do self check function automatically and clear any "Non hard" faults.
I shall be over around March and will bring the Rovacom with me if you wish-just PM me
Click to expand...
Thanks for that John, i will give it a try today and let you know my findings, if still giving problems i will pm you before you land in Nam.:D
Oh and yes the max is 29 but this is what i mean when i say dropping the temp by 1 degree on the hevac seems more like 5 or 6 judging by the drop in fan temp. How can i tell if the blend motor flap is fully open? thanks again.
 
Last edited:
have i been using my hevac wrong all of these years?
if i press the arrows, up or down , left or right set, the temperature changes with settings. this i take it is manual?
if i press the button in the middle of the fan control switch, the hevac says "auto" and it turns the fans to full, diverts all air to screen, turns front screen heaters on, turns both heated seats on. this i only use too clear the windscreen?
 
In Auto which is the normal default mode, the temperature can be adjusted, the air distribution can't. In "Prog" mode which is for rapid demist, both screen heaters will come on together with high speed blowers. In manual mode, all adjustments to air distribution and blower speed can be made together with temp. changes. Pressing the Auto button will drop it out of manual mode and return to Auto.
 
John, tried all the above and all seems to be working fine, only thing i didn't try was the air line in the temp sensor, i got a compressor down the garage and will try that later, what will this tell me?
The temp needle on the dash only comes out of the blue also but still hot air from vents.
 
Behind that grille is a small fan which draws air over a temperature sensor. This sends the interior temperature of the cabin back to the HEVAC, which in turn automatically increases/decreases temperature to maintain set figure by moving the blend flaps. The small fan sometimes gets bunged up with dust & ****e and doesn't turn. You can check operation of the sensor by holding a cigarette lighter in front of it, you should hear the blowers increase in speed after a few seconds. You can also check the operation of the solar sensor which is located in the centre of the dash between the demist vents in the same way by shining a bright torch on it.
 
Ref. the temp gauge...they are not that precise. As the handbook says, as long as it's out of the blue and below the red, it's o.k. If it's a V8 and you have about £20 spare+ cost of new antifreeze, change the stat. Or you could always take a thermometer and check the temp. next to the gauge sender on the inlet manifold, against the spec. on RAVE
 
No it's a diesel so aint that bothered anyway, it doesn't overheat or run cold so a job for the summer me thinks. As for the hevac, all seems to be working fine. Set to auto tried different temps and fans slow down and speed up as they should so i'll prob wait until you're back over and meet up with you if that's ok with you. Thanks again John.;)
 
Glad you feel happier. Doesn't do any harm to drive the blend motors through the range in manual, say once a month as most of the time they only move a small amount and it helps keep the potentiometer tracks clean. Also remember the tip for blowing the grille out, say one every 3 months.
I'll bring the kit over anyway in March and PM yourself & Mark when I have firmed up the ferry.
 
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