Radiator Fan Wiring help!?
Discussion
Hi,
I've had a look at the forum, seen plenty of instances where the reverse is true but I think this is unique!
The car is a 1993 chimaera 430. Pre serp, early example. Had it about 10 years, used to have an account on here too but my email address linked to it got closed so hello again!
The issue...
I've been having trouble with overheating. Especially in traffic. So I've gone to lots of trouble to address the system as a whole.
- I installed a temperature sensor on the swirl pot inward pipe which allows me to see the live temperature of the coolant.
- then I got paranoid because it's consistently higher than the dashboard temperature gauge!
- So, I wired in an override switch to the otter switch (swirl pot location) which just makes across the otter switch spade connectors. Great!
- But it still got hot in traffic.
- So I recored the rad. Lovely job by a local guy. Not cheap but quality.
- But it still got hot in traffic.
- So, to address heat soak inputs, I wrapped the exhaust from headers to the bottom of the downpipe.
- But it still got hot in traffic.
- I noticed my original fans were a bit weak so I replaced them with a really lovely spal set that shift nearly 2000l/m or something.
- But it still got hot in traffic.
- Increasingly frustrated I lifted the bonnet and looked to see the fans weren't running (I did test them by the way when I installed them)
- I realised they were not turning back on if they'd already been on and gone off. I stopped the car fully, restarted it with fans and it sat outside the train station while I waited for a colleague idling, with fans, and normalised at 76 degrees.
- Finally, we're getting somewhere. Although I learned that I probably didn't need the rad recoring, the heat wrap or the fans lol. The problem is in the switching.
Previously
- fans switch on and off but won't restart when the engine is running
- fans switch on and off as much as I like when the engine is off
Now (only a few days later) there are inexplicably different rules.
- fans cut whenever the engine is running
- I took the relay out and put a link wire in, they still cut out so problem is on the power circuit presumably.
- fans switch on and off as much as I like when the engine is off
Some details
- fans share a single relay (position 7)
- Fans share a (switching) fuse (position 21)
- Fans share a (power) fuse (position 3)
- I've noticed the fans spin down slowly, a good 10s from running to stopped.
Questions:
- What's the consensus? Is there anything I've overlooked?
- does anyone know where the radiator fans earth to please?
What should I do?
- I can see a couple of options here, on one hand I could try to figure all this out and repair whatever is going on with the power circuit
- Or I could just put in a new circuit for fan power and switching control.
- I'll do a video, and post it below, please take a look if you have time.
I've had a look at the forum, seen plenty of instances where the reverse is true but I think this is unique!
The car is a 1993 chimaera 430. Pre serp, early example. Had it about 10 years, used to have an account on here too but my email address linked to it got closed so hello again!
The issue...
I've been having trouble with overheating. Especially in traffic. So I've gone to lots of trouble to address the system as a whole.
- I installed a temperature sensor on the swirl pot inward pipe which allows me to see the live temperature of the coolant.
- then I got paranoid because it's consistently higher than the dashboard temperature gauge!
- So, I wired in an override switch to the otter switch (swirl pot location) which just makes across the otter switch spade connectors. Great!
- But it still got hot in traffic.
- So I recored the rad. Lovely job by a local guy. Not cheap but quality.
- But it still got hot in traffic.
- So, to address heat soak inputs, I wrapped the exhaust from headers to the bottom of the downpipe.
- But it still got hot in traffic.
- I noticed my original fans were a bit weak so I replaced them with a really lovely spal set that shift nearly 2000l/m or something.
- But it still got hot in traffic.
- Increasingly frustrated I lifted the bonnet and looked to see the fans weren't running (I did test them by the way when I installed them)
- I realised they were not turning back on if they'd already been on and gone off. I stopped the car fully, restarted it with fans and it sat outside the train station while I waited for a colleague idling, with fans, and normalised at 76 degrees.
- Finally, we're getting somewhere. Although I learned that I probably didn't need the rad recoring, the heat wrap or the fans lol. The problem is in the switching.
Previously
- fans switch on and off but won't restart when the engine is running
- fans switch on and off as much as I like when the engine is off
Now (only a few days later) there are inexplicably different rules.
- fans cut whenever the engine is running
- I took the relay out and put a link wire in, they still cut out so problem is on the power circuit presumably.
- fans switch on and off as much as I like when the engine is off
Some details
- fans share a single relay (position 7)
- Fans share a (switching) fuse (position 21)
- Fans share a (power) fuse (position 3)
- I've noticed the fans spin down slowly, a good 10s from running to stopped.
Questions:
- What's the consensus? Is there anything I've overlooked?
- does anyone know where the radiator fans earth to please?
What should I do?
- I can see a couple of options here, on one hand I could try to figure all this out and repair whatever is going on with the power circuit
- Or I could just put in a new circuit for fan power and switching control.
- I'll do a video, and post it below, please take a look if you have time.
Edited by DunkG on Tuesday 26th May 10:19
Bypassing the relay and not working suggests either poor contact at the fan connectors or a bad ground. Ground is at the o/s front lower chassis bolt which is a pain to get to but problems do happen here with corrosion and loose bolts.
I would add a temporary good ground if the connector checks out and see how it goes.
Fans also have a direction depending on how they are wired and which way the fan blades are, so make sure they are running correctly ie sucking fresh air into the engine bay and not pushing engine bay heat through the rad. ( think i have that right)
I would add a temporary good ground if the connector checks out and see how it goes.
Fans also have a direction depending on how they are wired and which way the fan blades are, so make sure they are running correctly ie sucking fresh air into the engine bay and not pushing engine bay heat through the rad. ( think i have that right)
Edited by Belle427 on Monday 25th May 14:58
Thanks Belle!
Yes, the fans are 100% turning the correct way.
I've located the earth point. Quite easy as the car is on stands with the wheels off. Assuming I've found the right point anyway...
Everything was tight and looked like it should, I got some continuity too when I tested it from rad fan connector -ve pin
The connectors on the fan look fine too.
I would link to my video but it won't let me post a link (fair enough) to my YouTube account which is called "hysterically inaccurate" and the video is called "TVR radiator fan piston heads help!"
Yes, the fans are 100% turning the correct way.
I've located the earth point. Quite easy as the car is on stands with the wheels off. Assuming I've found the right point anyway...
Everything was tight and looked like it should, I got some continuity too when I tested it from rad fan connector -ve pin
The connectors on the fan look fine too.
I would link to my video but it won't let me post a link (fair enough) to my YouTube account which is called "hysterically inaccurate" and the video is called "TVR radiator fan piston heads help!"
Edited by DunkG on Monday 25th May 16:47
Here's a link to your radiator video:
https://youtu.be/bhbWCXn1_-U?si=ICT9Wy8z5XJF2tWI
Sorry can't help with the problem!
https://youtu.be/bhbWCXn1_-U?si=ICT9Wy8z5XJF2tWI
Sorry can't help with the problem!
Edited by FunkyGibbon on Monday 25th May 16:56
You have pointed out one main earth but there is another one underneath the fan on the off side where several wires earth at the front of the chassis:
TVR Chimera/Grifith earth points:
1. A main earthing point is on the left hand side of the tunnel under the whale tail and dash.
2. The second is on the right hand side under the whale tail and dash.
3. A third at the front offside where the body is bolted to the chassis.
4. The fourth is at the rear where the body is bolted to the chassis, the lower near side bolt.
5. The main engine earth has two leads from the engine loom and is connected to the chassis offside by a substantial cable.
6. The engine loom has two more earth leads connecting to the rear nearside of the engine.
TVR Chimera/Grifith earth points:
1. A main earthing point is on the left hand side of the tunnel under the whale tail and dash.
2. The second is on the right hand side under the whale tail and dash.
3. A third at the front offside where the body is bolted to the chassis.
4. The fourth is at the rear where the body is bolted to the chassis, the lower near side bolt.
5. The main engine earth has two leads from the engine loom and is connected to the chassis offside by a substantial cable.
6. The engine loom has two more earth leads connecting to the rear nearside of the engine.
Evening All,
I've been in the garage and dug around for the earth. Found it!
Noting Belles comment about belling out (aha!), I did anyway and found I got continuity.
I made up some connectors to move the earth to the one I pointed out previously in the wheel arch and gave it a try. Basically nothing changed but I recorded a video of it anyway.
Still can't share links so please search for "TVR radiator fan piston heads help 2!" Or access it via the link that FunkyGibbon kindly posted a few comments previous.
And as before, thanks for the tips!
I've been in the garage and dug around for the earth. Found it!
Noting Belles comment about belling out (aha!), I did anyway and found I got continuity.
I made up some connectors to move the earth to the one I pointed out previously in the wheel arch and gave it a try. Basically nothing changed but I recorded a video of it anyway.
Still can't share links so please search for "TVR radiator fan piston heads help 2!" Or access it via the link that FunkyGibbon kindly posted a few comments previous.
And as before, thanks for the tips!
I would always use the battery as a good ground point just to rule that out personally.
You need to go back to basics really and test for voltages when the issue happens, maybe the ignition feed is playing up as that seems to be a common thing when you turn the car on/off.
Not sure if you have the wiring diagrams but if you can read them ok email me and I will send them to you.
You need to go back to basics really and test for voltages when the issue happens, maybe the ignition feed is playing up as that seems to be a common thing when you turn the car on/off.
Not sure if you have the wiring diagrams but if you can read them ok email me and I will send them to you.
As Belle said earlier it looks like and intermittent wiring problem. The old fan plug/sockets were a favourite for burning their contacts.
Have you tried connecting the fans directly from the battery bypassing all existing wiring and plugs? Then start the engine and see if anythinhg changes if it does it indicates an intermittent earth. Run a seperate known good earth or even back to the battery -ve and try again if that still fails start praying!
Have you tried connecting the fans directly from the battery bypassing all existing wiring and plugs? Then start the engine and see if anythinhg changes if it does it indicates an intermittent earth. Run a seperate known good earth or even back to the battery -ve and try again if that still fails start praying!
I've just made up a longer earth wire over my lunch break. Ran it to battery negative but now it's completely dead, can't even get the car to switch on let alone crank.
I've got voltage at the battery and it's charged.
Nothing else has changed.
Wondering if it's a broken cable or something because I can't get potential anywhere but the battery terminals.
I've got voltage at the battery and it's charged.
Nothing else has changed.
Wondering if it's a broken cable or something because I can't get potential anywhere but the battery terminals.
Edited by DunkG on Wednesday 27th May 13:09
If you look at the fuse/relay block there are some terminals with insulating goo covering them for protection.
Have you got volts on these terminals as that is the main +12v into more or less everything?
If not my later 96 car has a big fuse in a plastic oblong case that is not unknown to fail, not sure if your earlier car has one, but I think possibly you have the same.
Have you got volts on these terminals as that is the main +12v into more or less everything?
If not my later 96 car has a big fuse in a plastic oblong case that is not unknown to fail, not sure if your earlier car has one, but I think possibly you have the same.
I spoke to my mate after work and he said to check over what I'd done this lunchtime. Long story short, I've identified that the battery -ve ring crimp is broken so I can't fully tighten it down which is why none of the usual light came on. As soon as I backed off the nut on the earth strap, my lights all kicked straight in so I'll re-terminate my battery connectors and return to fixing these fans.
Thanks as always for your suggestions!
Thanks as always for your suggestions!
I promise you I didn't love removing my battery to sort the cable out! It's so far away when you have to lift it into its box at the bottom of the foot well isn't it!?
Anyway, the car is back in business, electrically it turns on and cranks and starts.
I also ran a wire from the fan -ve back to the battery and found slightly different symptoms...
With the engine off, same as before, can switch the fans as much as I like.
With the engine running, I can switch the fans but they kick for a couple of seconds and then stop so not sure what might cause that.
Anyway, the car is back in business, electrically it turns on and cranks and starts.
I also ran a wire from the fan -ve back to the battery and found slightly different symptoms...
With the engine off, same as before, can switch the fans as much as I like.
With the engine running, I can switch the fans but they kick for a couple of seconds and then stop so not sure what might cause that.
Probably one of the strangest issues I have seen on here!
Still stinks of a loose connection to me but I am excited to hear the outcome.
A test light may help you if your on your own testing to load up the circuit, something like an old headlight bulb is ideal as it will pull around 5 amps and give you a good visual too.
Testing for missing voltages when the fault happens is the way to go, if you have nothing at the otter switch/override switch when the fault occurs then you can work backwards.
Still stinks of a loose connection to me but I am excited to hear the outcome.
A test light may help you if your on your own testing to load up the circuit, something like an old headlight bulb is ideal as it will pull around 5 amps and give you a good visual too.
Testing for missing voltages when the fault happens is the way to go, if you have nothing at the otter switch/override switch when the fault occurs then you can work backwards.
DunkG said:
I promise you I didn't love removing my battery to sort the cable out! It's so far away when you have to lift it into its box at the bottom of the foot well isn't it!?
....
The battery box is secured by 2 bolts going through the floor. These are accessible by reaching underneath, it means the battery box can be slid out, there is enough slack in the leads to move it out quite some way. Being an early car, the box may be suspended slightly off the floor, you'll need to remove the wheel to access the bolts then, if there are any?....
If you do this, mark the floor with a pen first, trying to get it lined up again can be a problem.
There are threaded brass inserts glassed into the base of the box, and the bolts unfortunately often rust in.Edited by sixor8 on Friday 29th May 08:00
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