right my car keeps itself nice and cool when driving, temp guage sits between vertical and the line to the left ... ... but now when it idles at running temp the coolant light flashes for 10 seconds or so .. ... then the fan cuts in and the light goes out ... and so this cycle repeats over and over again with no change at all. so is this: A) my low speed on the fan isnt working and ive just not noticed b) rad fan switch is playing up and not kicking in early enough c) temp switch for guage is reading wrong to the dash and making the guage and light act daft!! what you reckon guys???
Hi have you checked the coolant level sensor in the coolant expansion tank(sensor in the top) If faulty will flash even when correct level,one easy test is a bit of wire between the contacts in the wiring plug-should go out(main wiring ok) remove wire light should come on(faulty sensor in tank) sounds like the temprature sensor is faulty(should read half way) sounds like fan is kicking at a odd time-could be faulty switch but make sure the temprature is reading right(as dash gauge is run separete from the switch sensor) I had similer faults on a mk2 scirocco inj (1990) hope this helps, Mark
bottle and lid are brand new so shudnt be that but will test. Went out and bridged pins on fan wiring and i have 2 speeds working. First fan speed cuts in when needle hits vertical (or what is vertical on mk2 dash) but the light flashes before this happens. 2nd fan speed never comes on. will change guage switch and rad fan switch 2mro and see what happens. wondering tho if clocks may be on way out as always suspected il temps are tad high ...
the cooling system sounds like it works just fine, my money is on the clocks or the temp sensor itself. if its a pre-90 mk2 there is a control relay for the level sensor above the fusebox, which may also be causing problems.
its a 1989 on digifant and was registered 13/04/1990. fairly sure its post 90. i have a new gen switch to fit when the service dept goes quiet would the voltage stabiliser or ignition switch affect either of these???
registered date doesnt mean much, might have sat on a forecourt for a while, ive seen loads of pre-90s on a G plate check the hazard switch, dash = pre-90, column = post-90 volt stab could effect it I guess, ign switch probably not unless the clocks switch off intermitantly as well?
hazard switch on column so i guess post 90. i asked about ign switch as twice now ive removed key and starter motor keeps buzzing until i remove batt.
yeah thats a 90specer, usually its nnot the ign switch causing that, but a dodgy starter motor. you can confirm this by disconnecting the red/black spade wire from the starter. if the buzzing stops its the ign switch, if it doesn't its your starter
Right fitted new sensor and stil the coolant light flashes. ive bridged the wiring to the bottle and this makes no difference, the light stil flashes. could this now be a wiring issue? how can i test wiring for the guage temp sensor.
ok that probably rules that out, the blue one is for the ecu, fan senasor is the one in the radiator does the rev counter do anything odd when the light starts flashing?
Nope everything on the dash is perfect. Rev counter fuel and all MFD items work perfectly and never miss a beat. Im gonna go through the earths later and put new connectors on those that are on the side of the head and fit a new voltage stabilizer at weekend. Have i missed anything obv ??? otherwise its new dash time ....
all that is what i would start with aye! what does the mfa recon the oil temp is when the light starts going off?
Oil temp reads anywhere between 98 and 102 depending on if ive just let it idle up to temp or been driving. The oil temp does alter quite quickly but a very small amount whilst driving ....
This is just it, temps never ever get hot, 120 miles on motorway at !!mph and it only reads 108 on oil temp. Found vw wiring tests for the light so will also do these.
Right found the original VW test plan for coolant temp guage in the magical blue books using the potentiometer to change voltage through the wiring ... the guage rises as reqd to vertical where the light comes on ... it then goes out and stays off until the guage reaches its max position where the light should be coming on. im now totally at a lost with it!! the guage appears to working correctly but the warning light isnt.
suggests to me the cluster is faulty. one thing, check if you have a random 42 or 43 relay on your fusebox. the very very early models had a strange missmatched dash clocks, late style but without a built in level sensor control unit as found on later clocks. i thought this was only early euro/us jetta models though, but you may as well double check!
