TM-4 alarm and Fan relay

[vitus992]

I have searched the threads but though the question has been asked I cant find any answers.
Has anybody fitted the fan override relay that can be fitted to the TM-4 alarm, if so is there a pdf or instructions anywhere - I have a Diesel Bongo.

Many thanks in advance.

Daren

[mikeonb4c]

I have searched the threads but though the question has been asked I cant find any answers.
Has anybody fitted the fan override relay that can be fitted to the TM-4 alarm, if so is there a pdf or instructions anywhere - I have a Diesel Bongo.

Many thanks in advance.

Daren

I've pondered on that (I have a TM2 so not sure if its an option anyway) but reckoned that the temp you set for triggering the alarm is a 'too late' value. I would want the fans coming on before that temperature was reached, so unless it has a separate temp threshold you can use for doing that then the situation isn't ideal. I have a manual over-ride switch on my scavenger fan and as I can easily see the TM2 readout I make my own decisions on when to switch the fan on. I think the same logic applied to radiator fans should work well. For example, if I see I am about to start climbing 1 in 3 hills, I'll switch the scavenger fan on in the knowledge that the hard work the engine is about to do warrants fans on ahead of the work to be done. For the rest, I rely on the standard sensors for switching on the various fans.

[vitus992]

Cheers Mike, I too have the scavenger fan override switch installed. On the TM-4 you can set a separate temperature for the cooling fan - if I only knew how to instal the thing!!

[teenmal]

The ETC switch should bring on your cooling fans, but if you need info this might help.

http://enginewatchdog.com/tm4%20installation.html

[vitus992]

Cheers for the Link but all that says is
If necessary seek professional advice on how the wire the relay to your vehicle. Do NOT connect any other wires to pins 85 and 86 of the relay. This may result in damage to the unit’s internal circuitry and will not be covered by warranty.

[g8dhe]

Which fan are you wanting to control and why do you need to override the ECU ?

[vitus992]

Cooling fans, it's all Part of the TM-4 alarm. I can set a temperature within the unit. If it's there I may as well use it - If I can fit the thing!

[teenmal]

Cooling fans, it's all Part of the TM-4 alarm. I can set a temperature within the unit. If it's there I may as well use it - If I can fit the thing!

If you Really need to fit an unnecessary add on scroll down for all the bumf that you should need ,you may also need to supply a relay.

http://enginewatchdog.com/tm4%20installation.html

Good LUCK

[vitus992]

Got the relay but all that advises is:
If necessary seek professional advice on how the wire the relay to your vehicle. Do NOT connect any other wires to pins 85 and 86 of the relay. This may result in damage to the unit’s internal circuitry and will not be covered by warranty.

Cheers for looking

[mikeonb4c]

Cheers Mike, I too have the scavenger fan override switch installed. On the TM-4 you can set a separate temperature for the cooling fan - if I only knew how to instal the thing!!

Ah! Now I understand your interest. And although I fully appreciate the argument that says it should be unnecessary, on an ageing Bongo I can also understand the interest in a back-up system that uses a device where you can see what is happening, and with a temperature display, just in case the ageing primary system fails to do what it should be doing. Anyway, we love gadgets - its part of the fun of Bongownership

[vitus992]

Not forgetting of course along with a gadget fiend I am a controll freak!

[Gefail]

Hello,
I have the fan override relay fitted on a TM4
I have the relay come on at 97c to bring on the scavenger fan, whilst the temp alarm is set at 99c. The running temp on our diesel bongo varies from 87c around town and 93c-95c at 60-70mph it hit 96c once on the way to somerset on a 8 hours bank holiday journey.
The two wires on the TM4 to the relay coil
And the normal open contact on the relay shorts the temp probe (near hand brake) with a series 330ohm (I think) resistor. It's never operated as yet, but I like the belt braces and piece of string it offers.
Cheers,
David

[vitus992]

David
I am reasonable at the oily bits and can do electrics via some sort of guides. I have a scav fan override switch installed (again from a pdf) so have you got the TM-4 actually kicking your radiator fans in or just the scav? If you have the radiator fans running off of it could I be really cheeky and ask for a picture of how its all wired please?
I could then create something for others to follow.

Many thanks

Daren

[Gefail]

Hi Daren,
I have the relay bring on the scavenger fan only, the way my thinking was I can bring the radiator fans on by turning the the air con on. I'll post a drawing when I get home.

[vitus992]

Hi David I have a manual switch on my scav fan with a resistor on there. Would love to see how you integrated the TM-4.
Many thanks

Daren