wohlmeyer

It’s in the frunk and a part of the cooling fans wiring harness. It doesn’t need a zip tie, it’s partially melted together.

So here is an update. I disconnected my temperature sensor at the manifold thinking it would make my fans come on immediately. Nothing happened. I checked for voltage at the relay and had 12 volts. I started probing around with my voltmeter after the relay until I found the connector pictured below. I shoved the ends of my volt meter prongs into the back of the connector and my fans came on. I pulled the prongs out and the fans shut off. I pulled on the connector wires and wiggled them a bit and the fans came on. So i think I need a new cooling fan harness and this will solve my issues.

Weird thing is, espritmon and free scan are both showing all is well. Ive tried multiple known good relays and there is no change. I think I have taken it as far as I can without a TECH-1. It might be time to trailer it to my tuner for a professional look under the hood.

Thanks for the reply. I have a place that sources ECU's. I have replaced my ECU once before. It is not hard, you just have to swap in the Chip and the Mem-cal. Blank ECU's are cheap. They get expensive when you want one that is plug and play. I will check the connections going in and out of the ECU. I know I have good sensors because I can watch them all function from espritmon. They all have the correct voltage and I can watch that temperature sensor rise all the way to critical, ALL the while, espritmon is reporting that the ECU is commanding the fans to turn on and sometimes they will and sometimes they will not. The car is also running rich and one of the solenoids (the one for the exhaust) gets hot, these are all the things that were happening the last time I replaced the ECU. The car ran great after that. not sure what I am going to do this time. I might just take it to my tuner and let them fool with it. My tuner sources the ECUs and has a TECH-1 on hand. He is what you might call a Lotus Esprit Wizard. The CAR WIZARD I have known for years. He is very good at a lot of general things and is very good with electrical diagnosis, however, he does not have a TECH-1 and even if he diagnosis a bad ECU, he does not know how to source them like my other guy.

Thanks for your reply. I have a box full of relays (11 years of ownership) that I have accumulated over the years. The relay that controls the fans I have 2 brand new ones and 2 of the yellow colored original Lotus relays. All 4 relays work just fine and for good measure I have tried all 4 in the slot. The relay clicks on but the fans do nothing, sometimes... Sometimes the fans will click on for at least 1 cooling cycle before they crap out and do not come on no matter what I do. I can turn the relay on and off with espritmon and sometimes the fans will come on when I do this...sometimes they will not. As far as ECU's go, i have replaced the ECU before. It is not a big deal. They are GM ECU's. All you have to do is switch over the Chip and Mem-cal. Bill

How would I know if the ecu is damaged? Everything I’m experiencing has all the signs and symptoms of a bad ecu.

Espritmon is also showing a random code 26 QDM. And the car is running rich. The QDM code 26 is not persistent. I can also manually turn the fans on with espritmon all the way until the first cooling cycle then espritmon won’t activate the fans anymore. Espritmon is also showing a random code 26 QDM. And the car is running rich. The QDM code 26 is not persistent. I can also manually turn the fans on with espritmon all the way until the first cooling cycle then espritmon won’t activate the fans anymore.

There is only one fan relay. its revised harness. there is nothing in the trunk. So the fans switch on at 87C through one full cooling down cycle then switch off and never come on again. The car will heat all the way up to redline and the fans wont move. If i turn the car off and let it cool all the way down. The exact same thing happens. car will heat up, fans will kick on and cool the car back down then the fans will turn off and wont come on again. Additionally, the vacuum solenoid valve, EBPV is getting hot but the other two solenoids are cool to the touch. not sure if any of this is related?

I have a 1995 Esprit S4s with revised harness. So this is a new one I have not seen in 11 years of ownership. My radiator fans will not come on. The three radiator fan fuses are good and the fuse that goes to the relay is good and the relay works as I can turn it on and off with espritmon. With the car running, using espritmon, i press the fan on button and the relay clicks and the fans do nothing. I turn the A/C on and the fans do nothing. I dont see anything interesting on the wiring diagram after the fan control relay. The only thing I have had off the car is the earthing strap that runs between the driver and passenger seats as I had the seats out of the car. Where would you guys start to look at this point? Thanks

Yeah I will give it all another go before I decide to cut. If I do decide to cut, I’m going to take it to a body shop and have it professionally done as well as an access cover made so that it looks like it came out of Hethal that way.

There is nothing wrong with the valve, the cable is binding up somewhere as it has broken off the temperature selector knob and won’t budge. I can’t move the cable in or out, even with pliers but I can easily move the valve with the tip of my finger. When I pull the valve to the heated position as soon as I let my finger off of it, it snaps back to a center position presumably due to torsion on the cable. I’ve decided the cable needs replacing but I cannot reach any of the screws or nuts on the valve control mechanism in order to release the cable.

Well thanks for all the advice. Ian I looked at your refurb manual as well. Since I’m not British, I’m afraid I’m going to have to do this the caveman way rather than the British way. I’m going to power saw my way through and make a handy access panel because I’m not going to turn what should be a simple repair into a week long adventure simply because Lotus forgot to add an access port. I’m going to help Lotus with that problem by engineering my own access with some handy dandy power tools.

Can you describe how you managed to access the water valve? I can see it through the fuse box hole but cannot reach it, I’m considering cutting an access panel. Am I missing something?

Clean the connections on your sender to oil gauge. If still no joy replace the sender. SJ has them in stock. If you look around here there is also a lot of information on testing the sender and the wiring between the sender and the gauge. But If i had to guess, I would guess your sender is kaput. Blue arrow is sender. Link to other thread: http://www.thelotusforums.com/forums/topic/14704-low-oil-pressure-reading-intermittent/page-2

Thanks for all the detailed information and replies. Sorry about the simplicity of my question but I had my engine rebuilt 10K miles ago and I dont want to do it again any time soon so I am always paranoid about anything having to do with the cooling system on my car. Alex, you can get a new white bottle header tank from SJ sports cars, if you want a stainless steel one, lotus pbc has them but they are expensive.