manual fan switch

[neil0205]

does anyone know how to convert the cooling fans to a manual switch so u can turn them on when u want.my cerb is getting hot when going through traffic.it`s gets to 110! surely this isn`t right.

[mikesr]

It quite possibly isn't correct. Many people have reported the guage reading high. Depends on how the capillary runs through the engine bay. If its tie wrapped to the side of the water rail its in a hot spot near the exhaust manifold which tends to raise the reading.

The fans are switched on by the ECU which uses a separate electrical temp sensor. Plugging a laptp in and checking the temp the ECU is reporting will give you a feel for how high the guage reads above actual temp.

The ECU as standard turns the fans on at 95 and 97. The stat opens at 85/86 so the cooling system hots up another 10 degrees after the water is going through the rad before the fans kick in.

See this thread re the TCS chip that turns the fans on sooner to avoid the hike in temp.

[budaholic]

um! i'm quite sure the fans come on at 92 and 95, then they switch off at 88.

My gauge reads very high compared to actual temps, it used to enter the oil pressure area, and even though I knew the fans were coming on correctly, I was still getting my expansion tank venting excess pressure regularly.
I've just fitted the TCS chip and it brings the fans in nearer to the thermostat operating temps. recommended upgrade

Bud

[v8_oatz]

I have also just fitted this chip upgrade. Shockingly, when the original chip came out, one of the 'legs' was completely bent over. So since the car was new it cannot have been making any contact at all!

I have to say that sitting in traffic is now more bearable - recommend the upgrade!

[mikesr]

Memory is going. Not sure where I got 95/97 from.

Just checked a few chipfiles - seems to be rad 1 on at 92 and off at 90 and rad 2 on at 94 and off at 92.

[micky g]

Mine's on at 95/97 and off at around 90. Thing that bothers me is that the fan doesn't stay on unless the ignition is on, therefore find myself waiting a couple of min's for the fans to switch off after stopping from warm. This normal?

[cossiemetro]

is the chip upgrade as easy as it sounds open ecu pop chip in ???
no other mods needed??

[Alan JH]

I fitted the TCR "cooling" chip this afternoon to my Cerb 4.5. The hardest part, once I had found the ECU in the passenger footwell was removing the 4 allen screws on the cover - one of them was a sod. Pull the old chip out and replace with the new one. The fan now switches on at 90/92 degrees instead of 97/98.

[headcase]

neil0205 said:

does anyone know how to convert the cooling fans to a manual switch so u can turn them on when u want.my cerb is getting hot when going through traffic.it`s gets to 110! surely this isn`t right.

OK, its Sunday and i'm bored so here we go, i've dug out my copy of proteus and done you a diagram of how to wire a manual switch with the help of a relay.


For the relay use a single pole changeover type,

From the diagram use the supply from the ecu to power the relay (not the fan),
then use good quality cable from the battery to the relay and from the relay to the fan.
When running any cable from the + of your battery it is good practice to fit a fuse as close to the battery as possible this is just in case your new cable gets damaged then it will blow the fuse instead of setting on fire!
For the manual switch itself you need to use some kind of latchig switch because i dont think that you want to sit there holding the button in, the cabeling for this can be 'standard' low current type (because it is only switching the relay coil).
Evryone can now feel free to pick fault the only other thing that i could mention woul be to fit a diode across the relay coil to stop the back emf spiking the ecu!

Please note, use it at your own risk, i willnot be held responsible for anything going wrong, this is just a bit of free advice.

If you are interested then there are many more circuits like this (non of them are car related though) on my old defunked website set up for an old project [url]www.m.case.btinternet.co.uk[/url]


>> Edited by headcase on Sunday 21st May 20:12

[neil0205]

thanks everyone for your responses.I`ve gone for the option of ordering the new chip you seem to all recommend it,and it seems easier than the manual option (thanks for diagram i might use it if i`m still not happy).

[Tyre Smoke]

How much is this chip then? And where from?

Sounds like a plan for Le Mans!

[neil0205]

got it from here track-car-solutions.co.uk about 75pounds inc p+p