What Causes Tecma Rv Toilet Red Light? (Explained)

I thought I was the only one that was facing the problem of a permanent red light on my Tecma RV toilet. But after doing a bit of research, I found that apparently it is a very common problem that many users face. 

The red light is designed to turn on whenever the black tank attached to the Tecma Rv toilet reaches its maximum capacity. But as I have found out, they can stay on regardless whenever there is a problem with the sensor, electrical wiring or the macerator pump. 

So what do you do when you are in this situation? Well first you have to identify the exact cause and then you can think about a solution. Here I share some of the common reasons why the light is staying stubbornly red.


What Causes Tecma Rv Toilet Red Light?  

If you see the red light on the Tecma Rv toilet, it means that the flush function has been locked out and you won’t be able to flush your toilet for the time being. 

Let’s see why that keeps happening.

1. The Black Tank is Full

When the black tank of the Tecma RV toilet is full, the red light will flash if the sensor is working correctly. So if the black tank is full, the obvious solution is to simply empty the tank of all its contents. 

Make sure to wear your protective equipment and dump the black water first before dumping the gray water. Then shut off the valves and rinse through the sewer hose to remove any excess waste particles.

2. The Black Tank is Clogged

If the black tank is clogged, you will notice that there is a trickle of leaking water that is coming out of the tank. You will also have bad odors coming out of the tank if there is enough buildup of waste resulting in clogging. 

The best solution is to use a black tank treatment which involves pouring a specific enzyme and letting it sit in the tank for some time before dumping the tank. 

Another simple solution you can try is pouring hot water. You can also use a sewer snake and scrape the clogs off the tank’s insides. The cost of an RV treatment will range from $8 to $15.

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3. Faulty Sensor

Dirt, water and toilet paper can affect the sensors on the Tecma RV toilet and its capacity to detect waste levels, resulting in inaccurate readings as false red light warnings. 

To fix this, you will need to replace the sensors. If you don’t have any knowledge of the replacement process, you can contact a mechanic on this. Otherwise, you can follow the owner’s manual that explains in detail how to make the replacements correctly.

4. Sensor Fell Off

When the Tecma RV Toilet starts wrongly showing a red light, then check the sensors if they are attached or not. 

Use aluminum duct tape to reattach the sensor to the toilet. Make sure to install it correctly otherwise the red light will persist. The duct tape would not cost more than $2 or $3.  

5. High Resistance On Sensor Wires

If disconnecting or replacing the sensor does not work, then the problem might be extremely high resistance. If you use an ohmmeter on the sensor, you find that it shows a resistance reading of 620Ω.   

To solve this problem, you will need to get a 620-ohm resistor and connect it to the resistor. Doing this will trick the resistor into thinking the black tank is empty and hence glow green permanently.  

You can choose to use one with a slightly lower or higher resistance as long as the reading is close to 620 ohms. So a 560-ohm or 680-ohm resistor would also do. 

You can contact Thetford directly to send you one free of cost. Or you can get one yourself which will cost about $5-6.

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6. Faulty Macerator Pump

One of the 3 items that use up power from the source is the macerator pump. To check whether the macerator pump is faulty, take a fuse and connect it to the power while disconnecting the pump. 

If the fuse blows, then the problem is not with the macerator pump. If the fuse does not blow, then you have to replace the macerator pump. 

7. Frayed Wire Causing Short Circuit

Another common reason why the red light is staying on is due to a short circuit caused by a frayed wire. The short circuit caused a malfunction in the sensor leading to a misread, thus keeping the lights turning red. 

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The red light flashing on the Tecma RV toilet is a very common problem that users face which leads to so many questions in the users’ minds. Here we look at some of the most common questions asked by users.

Is there a temporary solution for the red light flashing on the Tecma RV toilet?

There is an emergency override function in case the red light flashes falsely. To engage it, you need to press and hold one of the flush buttons for at least 6-10 seconds.
This will immediately engage the flush function even if the tank is full (or presumably full).

Why does the sensor on the Tecma RV toilet show incorrect readings?

There are several reasons why the sensor shows incorrect readings. The sensor gets dirty as it comes into contact with dirt, dust, waste, water and toilet paper.
These contaminants can skew the readings that incorrectly show the tank is full.

What is the function of the macerator pump on the Tecma RV toilet?

The macerator pump in the Tecma RV toilet is designed to break up solid waste in the toilet so that it can be drained much more easily.

How often should I dump the waste from the black tank on my Tecma RV toilet?

I would recommend dumping the waste every few days. If you let the waste stay in the tank for enough time, there might be an excessive buildup of waste particles and the black tank will get clogged.

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When you find the red light flashing on your Tecma RV toilet, remember to check whether the waste level on the black tank is full. If so, then there is no problem and all you need is to get rid of the waste. 

Otherwise, check whether the sensor is clean or not. It would also be good to check whether the sensor is in a good functioning condition. Consider replacing it if it is in bad condition.

Make sure to check the wiring around the toilet so that the problem is not related to electrical connections.

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